elena has 60 colored pencils, and lucy has 26 colored pencils. howmany pencils must elena give to lucy so that elena will have 4 more colored pencils than lucy?

Answers

Answer 1

Answer:  15

Step-by-step explanation:

Given : Elena has 60 colored pencils, and Lucy has 26 colored pencils.

Total colored pencils = [tex]60+26=86[/tex]

Let 'x' denotes the number of pencils Lucy has when she get pencils from Elena , and Elena left with 'y' pencils.

Then, by considering the given information we have the following system :-

[tex]\text{Total pencils : }x+y=86-----(1)\\\\\text{Colored pencils left with Elena : }y=4+x-----(2)[/tex]

We can rewritten the equation (2) as

[tex]y-x=4[/tex]

Now, add equation (1) and (2), we get

[tex]2y=90\\\\\Rightarrow\ y=\dfrac{90}{2}=45[/tex]

Put the value of y in (2), we get

[tex]45=4+x\\\\\Rightarrow\ x=45-4=41[/tex]

It means, the number of pencils Lucy has now =41

The number of pencils Elena give to Lucy= [tex]41-26=15[/tex]

Hence, Elena must give 15 pencils to lucy so that elena will have 4 more colored pencils than Lucy.


Related Questions

A principal of $7,500 is invested in an account paying an annual rate of 5% find the amount in the account after 5 years if the account is compounded semi-annually quarterly and monthly the amount in the account after 5 years if the account is compounded semi-annually is

Answers

Answer:

$9142.46

Step-by-step explanation:

Use the compounded interest formula: [tex]A=P(1+\frac{r}{m} )^{m*t}[/tex]

Where

A is the accumulated amount after compounding (our unknown)

P is the principal ($7500 in our case)

r is the interest rate in decimal form (0.05 in our case)

m is the number of compositions per year (2 in our semi-annually case)

and t is the number of years (5 in our case)

[tex]A=P(1+\frac{r}{m} )^{m*t}= 7500 (1+\frac{0.05}{2} )^{2*5} =9142.4581996....[/tex]

We round the answer to $9142.46

For what value(s) of, if any, is the given vector parallel to = (4,-1)? (a) (8r,-2) (b) (8t, 21)

Answers

Answer:

r=1 and t= -21/2.

Step-by-step explanation:

Two vectors are parallel if both are multiples. That is, for a vector (x,y), the parallel vector to (x,y) will be of the form k(x,y) with k a real number. Then,

a) (8r, -2) = 2(4r,-1). Then, we need to have that r=1, in other case the first component wouldn't be 4 or the second component wouldn't be -1 and the vector (8r,-2) wouldn't be parallel to (4, -1).

b) for the case of (8t, 21) we need -1 in the second component and 4 in the first component, then let t= -21/2 to factorize the -21 and get 4 in the fisrt component and -1 in the second component.

[tex](8\frac{-21}{2}, 21) = -21(\frac{8}{2}, -1) = -21(4,-1)[/tex]. In other case,  the vector (8t, 21) wouldn't be parallel to (4,-1).

Vector (8r,-2) is parallel to (4,-1) when r = 1, whereas (8t, 21) cannot be made parallel to it. To determine this, we look for a scalar multiple relation between the vectors.

The question asks for what value(s) of, if any, the given vector is parallel to (4,-1). To determine if two vectors are parallel, we need to see if one is a scalar multiple of the other, which means their components in each dimension multiply by the same scalar. Let's examine the given options:

(a) (8r,-2) is parallel to (4,-1) if there exists a scalar 'k' such that 4k = 8r and -1k = -2. By solving these equations, we find that k = 2 satisfies both, meaning if r = 1, the vector is parallel to (4,-1).

(b) (8t, 21) cannot be made parallel to (4,-1) through any scalar multiplication, as there's no single scalar that would simultaneously satisfy the required equations for both components.

Therefore, vector (8r,-2) is parallel to (4,-1) for r = 1, while vector (8t, 21) cannot be parallel to it under any circumstances.

Solve the equation. 3 = n + 4 Question 3 options: 7 1 -1 12

Answers

Hey!

------------------------------------------------

Steps To Solve:

~Subtract n to both sides

3 - n = n + 4 - n

~Simplify

3 - n = 4

~Subtract 3 to both sides

3 - n - 3 = 3 - 4

~Simplify

n = -1

------------------------------------------------

Answer:

[tex]\large\boxed{n~=~-1}[/tex]

------------------------------------------------

Hope This Helped! Good Luck!

If the demand function for a commodity is given by the equation

p^2 + 16q = 1400

and the supply function is given by the equation

700 − p^2 + 10q = 0,

find the equilibrium quantity and equilibrium price. (Round your answers to two decimal places.)

equilibrium quantity
equilibrium price $

Answers

Answer:

Equilibrium quantity = 26.92

Equilibrium price is $31.13

Step-by-step explanation:

Given :Demand function : [tex]p^2 + 16q = 1400[/tex]

           Supply function : [tex]700 -p^2 + 10q = 0[/tex]

To Find : find the equilibrium quantity and equilibrium price.

Solution:

Demand function : [tex]p^2 + 16q = 1400[/tex]  --A

Supply function : [tex]p^2-10q=700[/tex] ---B

Now to find the equilibrium quantity and equilibrium price.

Solve A and B

Subtract B from A

[tex]p^2-10q -p^2-16q=700-1400[/tex]

[tex]-26q=-700[/tex]

[tex]26q=700[/tex]

[tex]q=\frac{700}{26}[/tex]

[tex]q=26.92[/tex]

So, equilibrium quantity = 26.92

Substitute the value of q in A

[tex]p^2 + 16(26.92) = 1400[/tex]

[tex]p^2 + 430.72 = 1400[/tex]

[tex]p^2 = 1400- 430.72[/tex]

[tex]p^2 = 969.28[/tex]

[tex]p = \sqrt{969.28}[/tex]

[tex]p = 31.13[/tex]

So, equilibrium price is $31.13

Which is relatively better: a score of 73 on a psychology test or a score of 41 on an economics test? Scores on the psychology test have a mean of 86 and a standard deviation of 15. Scores on the economics test have a mean of 48 and a standard deviation of 7.Choose the correct answer below.(A) The economics test score is relatively better because its z score is less than the z score for the psychology test score.(B) The psychology test score is relatively better because its z score is less than the z score for the economics test score.(C) The economics test score is relatively better because its z score is greater than the z score for the psychology test score.(D) The psychology test score is relatively better because its z score is greater than the z score for the economics test score.

Answers

Answer:

The correct option is: (D) The psychology test score is relatively better because its z score is greater than the z score for the economics test score.

Step-by-step explanation:

Consider the provided information.

For psychology test:

Scores on the psychology test have a mean of 86 and a standard deviation of 15.

Use the Z score test as shown:

[tex]z=\frac{x-\mu}{\sigma}[/tex]

Substitute x=73, μ=86 and σ=15 in the above formula.

[tex]z=\frac{73-86}{15}[/tex]

[tex]z=-0.866[/tex]

For economics test:

Scores on the economics test have a mean of 48 and a standard deviation of 7.

Use the Z score test as shown:

[tex]z=\frac{x-\mu}{\sigma}[/tex]

Substitute x=41, μ=48 and σ=7 in the above formula.

[tex]z=\frac{41-48}{7}[/tex]

[tex]z=-1[/tex]

The Z score of psychology test is greater than the Z score of economic test.

Thus, the correct option is: (D) The psychology test score is relatively better because its z score is greater than the z score for the economics test score.

Miki has been hired to repaint the face of the town clock. The clock face is really big! So, Miki divides the clock face into 12 equal sections to break up the work. Miki paints 1 section on Monday and 4 sections on Tuesday.

What fraction of the clock face does Miki paint on Tuesday?​

Answers

Answer:

4/12 or 1/3

Step-by-step explanation:

If you have 12 equal sections of a clock face, and 1/12 or 1 section is done Monday, then 4/12 or 1/3 is done on Tuesday if you exclude Monday's section. It's 4/12 or simplified to be 1/3 because it is only asking you what Miki has painted on Tuesday not Monday and Tuesday combined. How you get 4/12 to be 1/3 is that you take both the top number, (numerator), and the bottom number, (demoninator), and you divide them by the greatest common factor for both. Which is 4, so 4 divided by 4 is 1, and 4 divided into 12 is 3, (3 x 4 = 12), and that's how you get 1/3 for a fraction.

Hope this helps! :)

Miki paints 4 out of 12 sections of the clock face on Tuesday which is 1/3rd of the clock face.

Miki divides the clock face into 12 equal sections and paints 4 sections on Tuesday.

To find the fraction of the clock face painted on Tuesday, we look at the number of sections painted on that day compared to the total number of sections.

Given that Miki paints 4 out of 12 sections, we write this as a fraction:

4 (sections painted on Tuesday) / 12 (total sections)

This fraction can be simplified by dividing both the numerator and the denominator by their greatest common divisor, which is 4:

(4 / 4) / (12 / 4) = 1 / 3

A 40ft long ladder leaning against a wall makes an angle of 60 degrees with the ground. Determine the vertical height of which the ladder will reach.

Answers

Answer:

The vertical height, h = 34.64 feets

Step-by-step explanation:

Given that,

Length of the ladder, l = 40 ft

The ladder makes an angle of  60 degrees with the ground, [tex]\theta=60^{\circ}[/tex]

We need to find the vertical height of of which the ladder will reach. Let it iss equal to h. Using trigonometric equation,      

[tex]sin\theta=\dfrac{perpendicular}{hypotenuse}[/tex]

Here, perpendicular is h and hypotenuse is l. So,

[tex]sin(60)=\dfrac{h}{40}[/tex]

[tex]h=sin(60)\times 40[/tex]

h = 34.64 feets

So, the vertical height of which the ladder will reach is 34.64 feets. Hence, this is the required solution.

Suppose the manager of a shoe store wants to determine the current percentage of customers who are males. How many customers should the manager survey in order to be 99% confident that the estimated (sample) proportion is within 3 percentage points of the true population proportion of customers who are males?

Answers

Answer:

The minimum approximate size to reach a maximum estimation error of 0.03 and a 99% confidence is 752 units

Step-by-step explanation:

In calculating the sample size to estimate a population proportion in which there is no information on an initial sample proportion, the principle of maximum uncertainty is assumed and a ratio [tex]P = 1/2[/tex] is assumed. The expression to calculate the size is:

[tex] n=\frac{z_{\alpha /2}^2}{4 \epsilon^2} [/tex]

With

Z value (for 0.005) [tex] Z _ {\alpha / 2} = 1.64485 [/tex]

Significance level [tex] \alpha = 0.01 [/tex]

Estimation error [tex] \epsilon = 0.03 [/tex]

[tex] n=\frac{(1.64485)^2}{(4)(0.03)^2} = 751.5398[/tex]

The minimum approximate size to reach a maximum estimation error of 0.03 and a 99% confidence is 752 units

Final answer:

To determine the percentage of male customers with a margin of error of 3% at a 99% confidence level, the manager would need to survey approximately 1847 customers.

Explanation:

The question is related to the concept of statistics, and more specifically to the idea of a confidence interval

for a population proportion. When you want to be very sure about your estimates, you use a high level of confidence. The standard formula for calculating the sample size needed in order to get a certain margin of error at a certain confidence level is n = [Z^2 * P * (1-P)] / E^2. In this formula, n is the sample size, Z is the z-score associated with your desired level of confidence, P is the preliminary estimate of the population proportion, and E is the desired margin of error. If the manager doesn't have a precursory idea of what the proportion of male customers is, it's standard to use P = 0.5. The Z score for a 99% confidence interval is approximately 2.576. Substituting these values, the manager would need a sample size of approximately 1846 customers. For more accuracy, it's better to round up to the next nearest whole number, so the minimum sample size required would be 1847.

Learn more about confidence intervals here:

https://brainly.com/question/32278466

#SPJ3

The height, h, of a ball that is tossed into the air is a function of the time, t, it is in the air. The height in feet fort seconds is given by the function h(t) = -16t^2 + 96t What is the domain of the function? a) [0,00) b) (-0,co) Oc) (0,co) d) (0,5) e) none

Answers

Answer:

[tex][0,\infty)[/tex]

Step-by-step explanation:

We have been given that the height, h, of a ball that is tossed into the air is a function of the time, t, it is in the air. The height in feet fort seconds is given by the function [tex]h(t)=-16t^2+96t[/tex].

We are told that the height of the ball is function of time, which means time is independent variable.

We know that the domain of a function is all real values of independent variable for which function is defined.

We know that time cannot be negative, therefore, the domain of our given function would be all values of t greater than or equal to 0 that is [tex][0,\infty)[/tex].


Use the "rule of 72" to estimate the doubling time (in years) for the interest rate, and then calculate it exactly. (Round your answers to two decimal places.) 9% compounded annually.

"rule of 72" yr

exact answer yr

Answers

Answer:

According to the rule of 72, the doubling time for this interest rate is 8 years.

The exact doubling time of this amount is 8.04 years.

Step-by-step explanation:

Sometimes, the compound interest formula is quite complex to be solved, so the result can be estimated by the rule of 72.

By the rule of 72, we have that the doubling time D is given by:

[tex]D = \frac{72}{Interest Rate}[/tex]

The interest rate is in %.

In our exercise, the interest rate is 9%. So, by the rule of 72:

[tex]D = \frac{72}{9} = 8[/tex].

According to the rule of 72, the doubling time for this interest rate is 8 years.

Exact answer:

The exact answer is going to be found using the compound interest formula.

[tex]A = P(1 + \frac{r}{n})^{nt}[/tex]

In which A is the amount of money, P is the principal(the initial sum of money), r is the interest rate(as a decimal value), n is the number of times that interest is compounded per unit t and t is the time the money is invested or borrowed for.

So, for this exercise, we have:

We want to find the doubling time, that is, the time in which the amount is double the initial amount, double the principal.

is double the initial amount, double the principal.

[tex]A = 2P[/tex]

[tex]r = 0.09[/tex]

The interest is compounded anually, so [tex]n = 1[/tex]

[tex]A = P(1 + \frac{r}{n})^{nt}[/tex]

[tex]2P = P(1 + \frac{0.09}{1})^{t}[/tex]

[tex]2 = (1.09)^{t}[/tex]

Now, we apply the following log propriety:

[tex]\log_{a} a^{n} = n[/tex]

So:

[tex]\log_{1.09}(1.09)^{t} = \log_{1.09} 2[/tex]

[tex]t = 8.04[/tex]

The exact doubling time of this amount is 8.04 years.

A store gave a customer an allowance of $10.50 on a dress that originally sold for $285.99. How much did the customer pay for the dress if the sales tax was 6.5%?

Answers

Answer:

$ 293.40

Step-by-step explanation:

Given,

The allowance given by the store = $ 10.50,

The original cost of the dress = $ 285.99,

So, the cost of the dress after allowance = 285.99 - 10.50

= $ 275.49,

Now, the sales tax = 6.5 %,

Hence, the final amount of the dress after tax = (100+6.5)% of 275.49

= 106.5% of 275.49

[tex]=\frac{106.5\times 275.49}{100}[/tex]

[tex]=\frac{29339.685}{100}[/tex]

= $ 293.39685

$ 293.40

Final answer:

The customer paid $293.40 for the dress after subtracting the allowance and adding the sales tax, which was calculated and rounded to the nearest penny.

Explanation:

To calculate the final price the customer paid for the dress after receiving an allowance and including sales tax, we follow these steps:

Subtract the allowance from the original price of the dress: $285.99 - $10.50 = $275.49.Calculate the sales tax by converting the percentage to a decimal and multiplying it by the adjusted price: $275.49 × 0.065 = $17.90685.Round the sales tax to the nearest penny: $17.90685 rounded is $17.91.Add the rounded sales tax to the adjusted price to get the total amount paid: $275.49 + $17.91 = $293.40.

Therefore, the customer paid $293.40 for the dress after the allowance and including the 6.5% sales tax.

The constant-pressure specific heat of air at 25°C is 1.005 kJ/kg. °C. Express this value in kJ/kg.K, J/g.°C, kcal/ kg. °C, and Btu/lbm-°F.

Answers

Answer:

In kJ/kg.K - 1.005  kJ/kg degrees Kalvin.

In  J/g.°C  -  1.005 J/g °C

In kcal/ kg °C  0.240 kcal/kg °C

In Btu/lbm-°F   0.240 Btu/lbm degree F

Step-by-step explanation:

given data:

specific heat of air = 1.005 kJ/kg °C

In kJ/kg.K

1.005 kJ./kg °C = 1.005 kJ/kg degrees Kalvin.

In  J/g.°C

[tex]1.005 kJ/kg C \times (1000 J/1 kJ) \times (1kg / 1000 g) = 1.005 J/g °C[/tex]

In kcal/ kg °C

[tex]1.005 kJ/kg C \times (\frac{1 kcal}{4.190 kJ}) = 0.240 kcal/kg C[/tex]  

For   kJ/kg. °C to Btu/lbm-°F  

Need to convert by taking following conversion ,From kJ to Btu, from kg to lbm and from degrees C to F.

[tex]1.005 kJ/kg C \frac{1 Btu}{1.055 kJ} \times \frac{0.453 kg}{1 lbm} \times \frac{(5/9)\ degree C}{ 1\ degree F}  = 0.240 Btu/lbm degree F[/tex]

1.005 kJ/kg C =  0.240 Btu/lbm degree F

Exercise 0.2.9 : Verify that x = C 1 e − t + C 2 e 2 t is a solution to x ′′ − x ′ − 2 x = 0 . Find C 1 and C 2 to solve for the initial conditions x (0) = 10 and x ′ (0) = 0 .

Answers

Answer:

Since 2 and -1 are eigenvalues of the differential equation,

[tex]x(t) = c_{1}e^{-t} + c_{2}e^{2t}[/tex]

is a solution to the differential equation

-----------------------------------------------------------

The solution to the initial value problem is:

[tex]x(t) = \frac{20}{3}e^{-t} +  \frac{10}{3}e^{2t}[/tex]

Step-by-step explanation:

We have the following differential equation:

[tex]x'' - x' - 2x = 0[/tex]

The first step is finding the eigenvalues for this differential equation, that is, finding the roots of the following second order equation:

[tex]r^{2} - r - 2 = 0[/tex]

[tex]\bigtriangleup = (-1)^{2} -4*1*(-2) = 1 + 8 = 9[/tex]

[tex]r_{1} = \frac{-(-1) + \sqrt{\bigtriangleup}}{2*1} = \frac{1 + 3}{2} = 2[/tex]

[tex]r_{2} = \frac{-(-1) - \sqrt{\bigtriangleup}}{2*1} = \frac{1 - 3}{2} = -1[/tex]

Since 2 and -1 are eigenvalues of the differential equation,

[tex]x(t) = c_{1}e^{-t} + c_{2}e^{2t}[/tex]

is a solution to the differential equation.

Solution of the initial value problem:

[tex]x(t) = c_{1}e^{-t} + c_{2}e^{2t}[/tex]

[tex]x(0) = 10[/tex]

[tex]10 = c_{1}e^{-0} + c_{2}e^{2*0}[/tex]

[tex]c_{1} + c_{2} = 10[/tex]

---------------------

[tex]x'(t) = -c_{1}e^{-t} + 2c_{2}e^{2t}[/tex]

[tex]x'(0) = 0[/tex]

[tex]0 = -c_{1}e^{-0} + 2c_{2}e^{2*0}[/tex]

[tex]-c_{1} + 2c_{2} = 0[/tex]

[tex]c_{1} = 2c_{2}[/tex]

So, we have to solve the following system:

[tex]c_{1} + c_{2} = 10[/tex]

[tex]c_{1} = 2c_{2}[/tex]

[tex]2c_{2} + c_{2} = 10[/tex]

[tex]3c_{2} = 10[/tex]

[tex]c_{2} = \frac{10}{3}[/tex]

[tex]c_{1} = 2c_{2} = \frac{20}{3}[/tex]

The solution to the initial value problem is:

[tex]x(t) = \frac{20}{3}e^{-t} +  \frac{10}{3}e^{2t}[/tex]

Consider the following game of chance based on the spinner below: Each spin costs $3. If the spinner lands on B the player wins $8, if the spinner stops on C the player wins a dime otherwise the player wins nothing. Calculate the players expected winnings. Express your answer to at least three decimal places in dollar form. .

Answers

Final answer:

To calculate the expected winnings of the spinner game, one needs the probabilities of landing on specific segments. The expected value is found by summing the products of each outcome's probability and its monetary value, subtracting the cost of playing. Without these probabilities, an exact calculation cannot be provided.

Explanation:

To calculate the player's expected winnings in the game with the spinner, we need to understand the concept of expected value, which is essentially the average outcome if the game was played many times. For this game, we are given the following payouts: if the spinner lands on B, the player wins $8; if the spinner lands on C, the player wins $0.10 (a dime); otherwise, the player wins nothing. In addition, each spin costs $3, which will be factored into the expected winnings as a negative value.


Unfortunately, we do not have the probabilities of landing on B or C. Expected value is usually calculated by multiplying the probability of each outcome by its corresponding value and then summing those products. The general formula is Expected value = Σ(Probability of outcome × Value of outcome) - Cost per play.


Without the specific probabilities or the number of segments on the spinner, we cannot calculate the exact expected winnings. However, if hypothetical probabilities were provided, the calculation would follow the structure of: (Probability of landing on B × $8) + (Probability of landing on C × $0.10) - $3.


Calculate the present value of the annuity. (Round your answer to the nearest cent.)

$1300 monthly at 6.4% for 30 years

Answers

Answer:

Ans. the present value of $1,300/month, at 6.4% compounded monthly for 360 months (30 years) is $207,831.77

Step-by-step explanation:

Hi, first, we have to turn that 6.4% compound monthly rate into an effective rate, one that meets the units of the payment, in our case, effective monthly, that is:

[tex]r(EffectiveMonthly)=\frac{r(CompMonthly)}{12} =\frac{0.063}{12} =0.005333[/tex]

Therefore, our effective monthly rate is 0.5333%, and clearly the time of the investment is 30 years*12months=360 months.

Now, we need to use the following formula.

[tex]Present Value=\frac{A((1+r)^{n}-1) }{r(1+r)^{n} }[/tex]

Everything should look like this.

[tex]Present Value=\frac{1,300((1+0.005333)^{360}-1) }{0.005333(1+0.005333)^{360} }[/tex]

Therefore

[tex]PresentValue=207,831.77[/tex]

Best of luck.

The quantity demanded x for a certain brand of MP3 players is 100 units when the unit price p is set at $100. The quantity demanded is 1100 units when the unit price is $50. Find the demand equation.

P=

Answers

Answer:

x = 2100 - 20p

Step-by-step explanation:

Let the quantity demanded be 'x'

unit price be 'p'

thus, from the given relation in the question, we have

p (100) = $100

and,

p (1100) = $50

now, from the standard equation for the line

[tex]\frac{\textup{p - p(100)}}{\textup{x - 100}}[/tex]  = [tex]\frac{\textup{p(1100) - p(100)}}{\textup{50 - 100}}[/tex]

or

[tex]\frac{\textup{p - 100}}{\textup{x - 100}}[/tex]  = [tex]\frac{\textup{50 - 100}}{\textup{1100 - 100}}[/tex]

or

1000 × (p - 100) = - 50 × ( x - 100 )

or

20p - 2000 = - x + 100

or

x = 2100 - 20p

Final answer:

The demand equation for the MP3 players can be determined using the given data points. By setting up a system of linear equations and solving for the values of a and b, we can find the demand equation Qd = 1500 - 10P.

Explanation:

The demand equation can be determined using the given information. We know that when the price is set at $100, the quantity demanded is 100 units, and when the price is $50, the quantity demanded is 1100 units.

We can set up a linear demand equation in the form Qd = a + bP, where Qd is the quantity demanded and P is the unit price. Using the two data points, we can solve for the values of a and b.

Substituting the first data point (100 units at $100) into the equation, we get 100 = a + b(100).Substituting the second data point (1100 units at $50) into the equation, we get 1100 = a + b(50).We now have a system of linear equations that we can solve to find the values of a and b.Solving the system of equations, we find that a = 1500 and b = -10.

Therefore, the demand equation is Qd = 1500 - 10P.

The length of a rectangle is 4 centimeters less than twice its width. The perimeter of the rectangle is 34 cm. What are the dimensions of the rectangle?
length = 14 cm; width = 9 cm
length = 10 cm; width=7
length = 7 cm; width = 10 cm
length = 9 cm; width = 8 cm

Answers

Let l and w be the length and width of the rectangle. We know that [tex]l=2w-4[/tex]

The formula for the perimeter is [tex]P=2(w+l)[/tex]

Using our substitution, it becomes

[tex]P=2(w+2w-4)=2(3w-4)=6w-8[/tex]

We know that the perimeter is 34, so we have

[tex]6w-8=34 \iff 6w=42 \iff w=7[/tex]

The length is 4 less than twice the width, so we have

[tex]l=2\cdot 7 - 4 = 10[/tex]

Find two vectors in R2 with Euclidian Norm 1
whoseEuclidian inner product with (3,1) is zero.

Answers

Answer:

[tex]v_1=(\frac{1}{10},-\frac{3}{10})[/tex]

[tex]v_2=(-\frac{1}{10},\frac{3}{10})[/tex]

Step-by-step explanation:

First we define two generic vectors in our [tex]\mathbb{R}^2[/tex] space:

[tex]v_1 = (x_1,y_1)[/tex][tex]v_2 = (x_2,y_2)[/tex]

By definition we know that Euclidean norm on an 2-dimensional Euclidean space [tex]\mathbb{R}^2[/tex] is:

[tex]\left \| v \right \|= \sqrt{x^2+y^2}[/tex]

Also we know that the inner product in [tex]\mathbb{R}^2[/tex] space is defined as:

[tex]v_1 \bullet v_2 = (x_1,y_1) \bullet(x_2,y_2)= x_1x_2+y_1y_2[/tex]

So as first condition we have that both two vectors have Euclidian Norm 1, that is:

[tex]\left \| v_1 \right \|= \sqrt{x^2+y^2}=1[/tex]

and

[tex]\left \| v_2 \right \|= \sqrt{x^2+y^2}=1[/tex]

As second condition we have that:

[tex]v_1 \bullet (3,1) = (x_1,y_1) \bullet(3,1)= 3x_1+y_1=0[/tex]

[tex]v_2 \bullet (3,1) = (x_2,y_2) \bullet(3,1)= 3x_2+y_2=0[/tex]

Which is the same:

[tex]y_1=-3x_1\\y_2=-3x_2[/tex]

Replacing the second condition on the first condition we have:

[tex]\sqrt{x_1^2+y_1^2}=1 \\\left | x_1^2+y_1^2 \right |=1 \\\left | x_1^2+(-3x_1)^2 \right |=1 \\\left | x_1^2+9x_1^2 \right |=1 \\\left | 10x_1^2 \right |=1 \\x_1^2= \frac{1}{10}[/tex]

Since [tex]x_1^2= \frac{1}{10}[/tex] we have two posible solutions, [tex]x_1=\frac{1}{10}[/tex] or [tex]x_1=-\frac{1}{10}[/tex]. If we choose [tex]x_1=\frac{1}{10}[/tex], we can choose next the other solution for [tex]x_2[/tex].

Remembering,

[tex]y_1=-3x_1\\y_2=-3x_2[/tex]

The two vectors we are looking for are:

[tex]v_1=(\frac{1}{10},-\frac{3}{10})\\v_2=(-\frac{1}{10},\frac{3}{10})[/tex]

The two vectors in R2 with Euclidean Norm 1 that are orthogonal to (3,1) are (1/√10, -3/√10) and (-1/√10, 3/√10).

To find two vectors in R2 with Euclidean Norm 1 whose Euclidean inner product with (3,1) is zero, we need to look for vectors that are orthogonal to (3,1). The Euclidean inner product of two vectors (x, y) and (3,1) is calculated by (3x + y). To have an inner product of zero, we need 3x + y = 0. Also, we want the vectors to have a Euclidean Norm (or length) of 1, so we need to satisfy the equation x2 + y2 = 1.

Solving these two equations together, we get that y=-3x for orthogonality, and substituting this into the norm equation gives x2 + 9x2 = 1, or 10x2 = 1. This gives two solutions for x, which are x = 1/√10 or x = -1/√10. For y we get correspondingly y = -3/√10 or y = 3/√10.

The two vectors in R2 with Euclidean Norm 1 that are orthogonal to (3,1) are therefore (1/√10, -3/√10) and (-1/√10, 3/√10).

This year, Druehl, Inc., will produce 57,600 hot water heaters at its plant in Delaware, in order to meet expected global demand. To accomplish this, each laborer at the plant will work 160 hours per month. If the labor productivity at the plant is 0.15 hot water heaters per labor-hour, how many laborers are employed at the plant?

Answers

Answer:

2400 laborers

Step-by-step explanation:

Let N be the amount of laborers employed at the plant. The amount of heaters produced by all workers in an hour is:

heaters = 0.15heaters/hour * N

In a month the total amunt of heaters will be:

heaters = 0.15 * N * 160

Since this has to be 57600 to meet the expected demand:

57600 = 0.15 * N * 160   Solving for N we get:

N = 57600 / (0.15 * 160) = 2400 laborers

Perform a one-proportion z-test for a population proportion. Be sure to state the hypotheses and the P-Value. State your conclusion in a sentence. In an American Animal Hospital Association survey, 37% of respondents stated that they talk to their pets on the telephone. A veterinarian found this result hard to believe, so she randomly selected 150 pet owners and discovered that 54 of them spoke to their pet on the phone. Does the veterinarian have the right to be skeptical? Perform the appropriate hypothesis test using a significance level of 5%.

Answers

Answer:

There is not enough statistical evidence in the sample taken by the veterinarian to support his skepticism

Step-by-step explanation:

To solve this problem, we run a hypothesis test about the population proportion.

Proportion in the null hypothesis [tex]\pi_0 = 0.37[/tex]

Sample size [tex]n = 150[/tex]

Sample proportion [tex]p = 54/150 = 0.36[/tex]

Significance level [tex]\alpha = 0.05[/tex]

[tex]H_0: \pi_0 = 0.36\\H_a: \pi_0<0.36[/tex]

Test statistic [tex] = \frac{(p - \pi_0)\sqrt{n}}{\sqrt{\pi_0(1-\pi_0)}}[/tex]

Left critical Z value (for 0.01) [tex]Z_{\alpha/2}= -1.64485[/tex]

Calculated statistic = [tex]= \frac{(0.36 - 0.37)\sqrt{150}}{\sqrt{0.37(0.63)}} = -0.254[/tex]

[tex]p-value = 0.6003[/tex]

Since, test statistic is greater than critical Z, the null hypothesis cannot be rejected. There is not enough statistical evidence to state that the true proportion of pet owners who talk on the phone with their pets is less than 37%. The p - value is 0.79860.

Let A fa, b,c. B [a, b, d), and C tb, d,e. Find the union of A and B, and then the union of this with C. Also, find the union of the B and C and then the union of this with A. Try to formulate what you have observed.

Answers

Answer:  A ∪ B = {a, b, c, d}

               (A ∪ B) ∪ C =  = {a, b, c, d, e}

               B ∪ C =  = {a, b, d, e}

               (B ∪ C) ∪ A  =  = {a, b, c, d, e}

Step-by-step explanation:

A = {a, b, c}       B = {a, b, d}         C = {b, d, e}

Union means "to join" so combine the sets to form a union.

A ∪ B = {A & B}

         = {a, b, c & a, b, d}

         = {a, b, c, d}          because we do not need to list a & b twice

(A ∪ B) ∪ C = {(A ∪ B) & C)

                  = {a, b, c, d & b, d, e}

                  = {a, b, c, d, e}     because we do not need to list b & d twice

B ∪ C = {A & B}

         = {a, b, d & b, d, e}

         = {a, b, d, e}           because we do not need to list b & d twice

(B ∪ C) ∪ A = {(B ∪ C) & A)

                  = {a, b, d, e & a, b, c}

                  = {a, b, c, d, e}     because we do not need to list a & b twice

Final answer:

We utilized set theory to find the union of sets A, B, and C in different orders and observed that the associative property of union holds true, meaning the order of union operations does not change the outcome which is {a, b, c, d, e}.

Explanation:

To answer this student's question, we can apply set theory concepts, specifically the concepts of the union and associativity.

Given sets A = {a, b, c}, B = {a, b, d}, and C = {b, d, e}, the union of these sets can be found as follows:

The union of A and B is A ∪ B = {a, b, c, d} - the set containing all elements from both A and B.The union of A ∪ B with C is (A ∪ B) ∪ C = {a, b, c, d, e} - the set containing all elements from A, B, and C.Similarly, the union of B and C is B ∪ C = {a, b, d, e}.The union of B ∪ C with A is (B ∪ C) ∪ A = {a, b, c, d, e}.

From these operations, we observe that regardless of the order in which we take the union of the three sets, the result is the same. This demonstrates the associative property of union in set theory, where the order in which unions are performed does not affect the final outcome. We can generalize this as A ∪ (B ∪ C) = (A ∪ B) ∪ C = A ∪ B ∪ C.

The finishing time for cyclists in a race are normally distributed with an unknown population mean and standard deviation. If a random sample of 25 cyclists is taken to estimate the mean finishing time, what t-score should be used to find a 98% confidence interval estimate for the population mean?

Answers

Answer:

The T-score is 2.49216

Step-by-step explanation:

A 98% confidence interval should be estimated for the end times of cyclists. Since the sample is small, a T-student distribution should be used, in such an estimate. The confidence interval is given by the expression:

[tex][\bar x -T_{(n-1,\frac{\alpha}{2})} \frac{S}{\sqrt{n}}, \bar x +T_{(n-1,\frac{\alpha}{2})} \frac{S}{\sqrt{n}}][/tex]

[tex]n = 25\\\alpha = 0.02\\T_{(n-1;\frac{\alpha}{2})}= T_{(24;0.01)} = 2.49216[/tex]

Then the T-score is 2.49216

Answer:

2.485

Step-by-step explanation:

The augmented matrix of a consistent system of five equa- tions in seven unknowns has rank equal to three. How many parameters are needed to specify all solutions?

Answers

Answer:

4 parameters are necessary to specify all solutions and correspond to the number of free variables of the system.

Step-by-step explanation:

Remember that the number of free variables of a system is equal to m-rank(A) where m is the number of unknowns variables and A is the matrix of the system.

Since the system is consistent and the rank of the matrix is 3 then echelon form of the augmented matrix has two rows of zeros.

Then m-rank(A)=7-3=4.

Find the two values of k for which y(x) = e^kx is a solution of the differential equation y'' - 20y' + 91y = 0. Preview smaller value = larger value = Preview

Answers

Answer:

The values of k are

1) k = 7.

2) k= 13

Step-by-step explanation:

The given differential equation is

[tex]y''-20y'+91y=0[/tex]

Now since it is given that [tex]y=e^{kx}[/tex] is a solution thus it must satisfy the given differential equation thus we have

[tex]\frac{d^2}{dx^2}(e^{kx})-20\frac{d}{dx}e^{kx}+91e^{kx}=0\\\\k^{2}\cdot e^{kx}-20\cdot k\cdot e^{kx}+91e^{kx}=0\\\\e^{kx}(k^{2}-20k+91)=0\\\\k^{2}-20k+91=0[/tex]

This is a quadratic equation in 'k' thus solving it for k we get

[tex]k=\frac{20\pm \sqrt{(-20)^2-4\cdot 1\cdot 91}}{2}\\\\\therefore k=7,k=13[/tex]

Final answer:

The two values of k satisfying the differential equation y'' - 20y' + 91y = 0 are found by substituting y(x) = e^kx into the equation, resulting in a quadratic equation k^2 - 20k + 91 = 0. Solving this yields the values k = 7 and k = 13.

Explanation:

To find the two values of k for which y(x) = ekx is a solution to the differential equation y'' - 20y' + 91y = 0, we start by differentiating the function y(x) = ekx twice to get the first and second derivatives, y' = kekx and y'' = k2ekx respectively. Substituting these into the given differential equation, we get:

k2ekx - 20kekx + 91ekx = 0.

Factor out ekx which is always positive and thus cannot be zero, we obtain a quadratic equation in terms of k:

k2 - 20k + 91 = 0.

Solving this quadratic equation gives us the two values of k. The solutions are obtained by finding the roots of the equation which involves factoring or using the quadratic formula. These will be the two constants we are looking for.

The characteristic equation is factorable and results in (k - 7)(k - 13) = 0. Therefore, the two values of k are 7 and 13, which are the smaller value and larger value respectively.

Dave received 120$ for his birthday from his parents and his friends. He went on a shopping spree and spent 2/5 of his money on a t-shirt and 1/6 on mountain bike magazines. How much money does he have left.

Answers

Answer: 52$

Step-by-step explanation:

The money Dave spent on a t-shirt is obtained multiplying 120$ by the fraction 2/5

120(2/5) = 48$

And the money he spent on mountain bike magazines is obtained multiplying 120$ by the fraction 1/6

120(1/6)= 20$

The money he has left is:

120$ - 48$ -20$ = 52$

Which point is a solution to the inequality shown in this graph?

Answers

Answer:

Step-by-step explanation:

the answers are the points in the shaded region so plot the points and see which one is in the blue area so 3,-1

Answer:

A. (3,-1)

Step-by-step explanation:

In order to solve this you just have to search for the point in the graph, if the points are located in theline that the graph shows then they are actually a solution for the inequality shown, since the only point that is actually on the line that is shown in the graph is (3,-1) then that is the correct answer.

Researchers have created every possible "knockout" line in yeast. Each line has exactly one gene deleted and all the other genes present (Steinmetz et al. 2002). The growth rate - how fast the number of cells increases per hour - of each of these yeast lines has also been measured, expressed as a multiple of the growth rate of the wild type that has all the genes present. In other words, a growth rate greater than 1 means that a given knockout line grows faster than the wild type, whereas a growth rate less than 1 means it grows more slowly. Below is the growth rate of a random sample of knockout lines:

0.8, 0.98, 0.72, 1, 0.82, 0.63, 0.63, 0.75, 1.02, 0.97, 0.86

What is the standard deviation of growth rate this sample of yeast lines (answer to 3 decimals)?

Answers

Answer: 0.144

Step-by-step explanation:

Formula to find standard deviation: [tex]\sigma=\sqrt{\dfrac{\sum_{i=1}^n(x_i-\overline{x})^2}{n-1}}[/tex]

Given : The growth rate of a random sample of knockout lines:-

0.8, 0.98, 0.72, 1, 0.82, 0.63, 0.63, 0.75, 1.02, 0.97, 0.86

Here ,

[tex]\overline{x}=\dfrac{\sum_{i=1}^{10}x_i}{n}\\\\=\dfrac{0.8+0.98+0.72+1+0.82+0.63+0.63+ 0.75+1.02+ 0.97+ 0.86}{10}\\\\=\dfrac{9.18}{10}\approx0.83[/tex]

[tex]\sum_{i=1}^n(x_i-\overline{x})^2=(-0.03)^2+(0.15)^2+(-0.11)^2+(0.17)^2+(-0.01)^2+(-0.2)^2+(-0.2)^2+(-0.08)^2+(0.19)^2+(0.14)^2+(0.03)^2\\\\=0.2075[/tex]

Now, the standard deviation:

[tex]\sigma=\sqrt{\dfrac{0.2075}{10}}=0.144048602909\approx0.144[/tex]

Hence, the standard deviation of growth rate this sample of yeast lines =0.144

Final answer:

The standard deviation of the growth rates for the given sample of yeast knockout lines is 0.148 when rounded to three decimal places.

Explanation:

To calculate the standard deviation of the growth rates of the yeast knockout lines, we first need to compute the mean (average) of the given data. Then, following the steps, we find the variance by calculating the difference between each value and the mean, squaring those differences, and finding their average. Finally, we take the square root of the variance to find the standard deviation.

Calculate the mean (average) of the sample data.Subtract the mean from each data point and square the result.Find the average of these squared differences, which gives us the variance.Take the square root of the variance to get the standard deviation.

Here are the calculations using the given growth rates:

Mean (average) = (0.8 + 0.98 + 0.72 + 1 + 0.82 + 0.63 + 0.63 + 0.75 + 1.02 + 0.97 + 0.86) / 11 = 0.836

[tex]Variance = [(0.8 - 0.836)^2 + (0.98 - 0.836)^2 + (0.72 - 0.836)^2 + (1 - 0.836)^2 + (0.82 - 0.836)^2 + (0.63 - 0.836)^2 + (0.63 - 0.836)^2 + (0.75 - 0.836)^2 + (1.02 - 0.836)^2 + (0.97 - 0.836)^2 + (0.86 - 0.836)^2] / (11 - 1)[/tex]

Variance = 0.021918

Standard Deviation = sqrt(variance) = sqrt(0.021918) ≈ 0.148

Therefore, the standard deviation of the sample growth rates, rounded to three decimal places, is 0.148.

The cubit is an ancient unit. Its length equals six palms. (A palm varies from 2.5 to 3.5 inches depending on the individual.) We are told Noah's ark was 300 cubits long, 50 cubits wide, and 30 cubits high. Estimate the volume of the ark (in cubic feet). Assume the ark has a shoe-box shape and that 1 palm = 3.10 inch.

Answers

The volume of the ark in cubic feet is  697500 feet³

What is a cuboid?

A cuboid is a 3D rectangular box.It hai 3dinemsion length, breath and height.volume of a cuboid is =(lenght*breath*height)

Calculation:-

1 cubit= 6 palm

1 palm=3.10 inches (given in the question)

⇒the volume of a cuboid is =(lenght*breath*height)

lenght=300 cubit

wide=50 cubit

height=30 cubit

volume=300*50*30

            450000 cubit³

since 1 cubit = 6 palm

        450000 cubit = 6*450000 palm

                                  2700000 palm

Again 1 palm = 3.10 inches (given in question)

       ∴ 2700000 palm= 2700000*3.10 inches

                                    =    8370000 inches³

   12 inch = 1 feet

  8370000 inch = 1/12*8370000 feet³

                             = 697500 feet³ (answer)

   

Learn more about cuboid here:-https://brainly.com/question/46030

#SPJ2

Final answer:

The estimated volume of Noah's Ark, assuming a shoe-box shape and given dimensions in cubits with one cubit equaling 1.55 feet, is approximately 1,583,737.5 cubic feet.

Explanation:

To estimate the volume of Noah's Ark using the measurements provided in cubits and converting them to a modern unit like feet, we first need to determine the length of a cubit in inches. As we are given that one cubit is equal to six palms and one palm is 3.10 inches, we can calculate the length of one cubit as follows:

1 cubit = 6 palms × 3.10 inches/palm = 18.6 inches.

Now, to convert inches to feet, we know that:

1 foot = 12 inches.

Therefore, one cubit in feet is:

1 cubit = 18.6 inches × (1 foot / 12 inches) = 1.55 feet.

Using this conversion, we can calculate the dimensions of the ark in feet:

Length = 300 cubits × 1.55 feet/cubit = 465 feet,Width = 50 cubits × 1.55 feet/cubit = 77.5 feet,Height = 30 cubits × 1.55 feet/cubit = 46.5 feet.

To find the volume of the ark, we will multiply these dimensions together:

Volume = Length × Width × Height,Volume = 465 feet × 77.5 feet × 46.5 feet,Volume = 1,583,737.5 cubic feet.

Therefore, the estimated volume of Noah's Ark is approximately 1,583,737.5 cubic feet.

volume of right trapezoid cylindar whole bases are B 16m, b 8m, height is 4m and length is 32m

Answers

Answer:

[tex]volume = 1536 m^3[/tex]

Step-by-step explanation:

given data;

B = 16m

b =8 m

height   H = 4 m

length  L = 32 m

volume of any right cylinder = (Area of bottom) \times (length)

Volume = A* L

The area of a trapezoid is

[tex]A=\frac{1}{2} H*(b+B)[/tex]

[tex]A =\frac{1}{2} 4*(8+16)[/tex]

[tex]A = 48 m^2[/tex]

therefore volume is given as  

volume = 48*32

[tex]volume = 1536 m^3[/tex]

Final answer:

To find the volume of the right trapezoidal cylinder, calculate the area of the trapezoid base and multiply by the cylinder's length. With B = 16m, b = 8m, and height = 4m, the trapezoid's area is 48m². The volume of the cylinder is 1536m³.

Explanation:

The volume of a right trapezoidal cylinder can be calculated using the area of the trapezoid as the base area and then multiplying by the height of the cylinder. Firstly, to calculate the area of the trapezoid (the base of the cylinder), we use the formula for the area of a trapezoid, which is ½ × (sum of the parallel sides) × height of the trapezoid. In this case, the parallel sides are B = 16m and b = 8m, and the height is 4m.

The area A of the trapezoid is then ½ × (16m + 8m) × 4m = ½ × 24m × 4m = 48m2. To find the volume of the trapezoidal cylinder, we multiply this area by the length of the cylinder, which is 32m. So, the volume V = 48m2 × 32m = 1536m3.

For the month of March in a certain​ city, 57​% of the days are cloudy. Also in the month of March in the same​ city, 55​% of the days are cloudy and foggy. What is the probability that a randomly selected day in March will be foggy if it is cloudy​?

Answers

Answer:

P(F | C) = 0.96

Step-by-step explanation:

Hi!

This is a problem on conditional probability. Lets call:

C = { cloudy day }

F = { foggy day }

Then F ∩ C = { cloudy and foggy day }

You are asked for P(F | C), the probability of a day being foggy given it is cloudy. By definition:

[tex]P(F|C)=\frac{P(F\bigcap C)}{P(C)}[/tex]

And the data you have is:

[tex]P(C) = 0.57\\P(F \bigcap C) =0.55[/tex]

Then: P(F | C) = 0.96

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