Proportions in Triangles (2)

Answer:

  see below

Step-by-step explanation:

The Law of Cosines tells you ...

  a² = b² + c² -2bc·cos(A)

Substituting the given values gives you ...

  a² = 4² +7² -2(4)(7)cos(52°)

Answer:

Pool will be filled in 280 hours

Step-by-step explanation:

Inlet pipe fills in  40 hours = 1 pool

Inlet pipe fills in 1 hours = [tex]\frac{1}{40}[/tex]

Drain pipe empty in 42 hours = 1 pool

Drain pipe empty in 1 hour =  [tex]\frac{1}{42}[/tex]

If both pipes are opened together

 then in pool fills in 1 hour =  [tex]\frac{1}{40}[/tex] -  [tex]\frac{1}{42}[/tex]

      on simplifying the right side ,we get  [tex]\frac{42-40}{(40)(42)}[/tex]

                                                                 =      [tex]\frac{2}{(40)(42)}[/tex]

                                                                 =     [tex]\frac{1}{840}[/tex]

      [tex]\frac{1}{840}[/tex]  pool fills in 1 hour

                       1 pool will be filled in 840 hours

    [tex]\frac{2}{3}[/tex]     pool is filled

empty pool =  1 - [tex]\frac{2}{3}[/tex] =  [tex]\frac{1}{3}[/tex]

therfore  [tex]\frac{1}{3}[/tex] pool will be filled in     [tex]\frac{1}{3}[/tex]X 840 =

                                                                                           = 280 hours

The  calculations indicate that 280 hours is the  time required to fill 2/3 of the pool with both pipes open.

Inlet Pipe Rate:

The inlet pipe can fill the pool in 40 hours.

Therefore, the rate of the inlet pipe is 1/40 pool per hour.

Drain Pipe Rate:

The drain pipe can empty the pool in 42 hours.

Therefore, the rate of the drain pipe is 1/42 pool per hour.

Combined Rate when both pipes are open:

The net rate when both pipes are open is the difference between their individual rates:

Net rate = (1/40) - (1/42)

Simplify the Net Rate:

Find a common denominator for 40 and 42, which is 840:

Net rate = (42 - 40) / 840 = 2/840 = 1/420

Time to Fill 2/3 of the Pool:

Set up the equation: Net rate * Time = 2/3

Substitute the net rate: (1/420) * Time = 2/3

Cross-multiply to solve for time: Time = (2/3) * (420/1) = 280

Therefore, it takes 280 hours to fill 2/3 of the pool when both the inlet and drain pipes are open.

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Answer:

The dimensions on the blueprints are 0.9 inches and 0.8 inches

Step-by-step explanation:

* Lets explain the relation between the drawing dimensions and

 the real dimensions

- A scale drawing make a real object with accurate sizes reduced

 or enlarged by a certain amount called the scale

- Ex: If the scale drawing is 1 : 10, so anything drawn with the size of

 1 have a size of 10 in the real so a measurement of 15 cm on the

 drawing will be 150 cm on the real

- In a scale drawing, all dimensions have been reduced by the same

 proportion

* Lets solve the problem

- On a set of blueprints for a new home, the contractor has

  established a scale of 0.5 in : 10 ft

∵ The drawing scale ratio must be in same unit

∴ Change the feet to inch

∵ 1 foot = 12 inches

∴ 10 feet = 10 × 12 = 120 inches

∴ The scale is 0.5 inches : 120 inches

- Simplify the scale by multiply it by 2

∴ The scale is 1 in : 240 in

- Lets find the dimensions on the blueprints

∵ The real dimensions are 18 feet and 16 feet

- Change the feet to inches

∴ 18 feet = 18 × 12 = 216 inches

∵ 16 feet = 16 × 12 = 192 inches

∵ The scale is 1 : 240

∴ 1/240 = x/216 ⇒ use cross multiplication

∴ 240 x = 216 divide both sides by 240

∴ x = 0.9 inch

∵ The scale is 1 : 240

∴ 1/240 = y/192 ⇒ use cross multiplication

∴ 240 y = 192 divide both sides by 240

∴ y = 0.8 inch

* The dimensions on the blueprints are 0.9 inches and 0.8 inches

Answer:

9

Step-by-step explanation:

[tex]\tt distance=\sqrt{(1-1)^2+(-4-5)^2}=\sqrt{0^2+9^{2}}=\sqrt{9^2} =9[/tex]

The formula for distance between two points is:

[tex]\sqrt{(x_{2} -x_{1})^{2} + (y_{2} -y_{1})^{2}}[/tex]

In this case:

[tex]x_{2} =1\\x_{1} =1\\y_{2} =-4\\y_{1} =5[/tex]

^^^Plug these numbers into the formula for distance like so...

[tex]\sqrt{(1-1)^{2} + (-4-5)^{2}}[/tex]

To solve this you must use the rules of PEMDAS (Parentheses, Exponent, Multiplication, Division, Addition, Subtraction)

First we have parentheses. Remember that when solving you must go from left to right

[tex]\sqrt{(1-1)^{2} + (-4-5)^{2}}[/tex]

1 - 1 = 0

[tex]\sqrt{(0)^{2} + (-4-5)^{2}}[/tex]

-4 - 5 = -9

[tex]\sqrt{(0)^{2} + (-9)^{2}}[/tex]

Next solve the exponent. Again, you must do this from left to right

[tex]\sqrt{(0)^{2} + (-9)^{2}}[/tex]

0² = 0

[tex]\sqrt{0 + (-9)^{2}}[/tex]

(-9)² = 81

[tex]\sqrt{(0 + 81)}[/tex]

Now for the addition

[tex]\sqrt{(0 + 81)}[/tex]

81 + 0 = 81

√81

^^^This can be further simplified to...

9

***Remember that the above answers are in terms of units

Hope this helped!

~Just a girl in love with Shawn Mendes

Answer:

See below in bold.

Step-by-step explanation:

Ship's vector:

Horizontal component = 30 cos 30  = 25.98.

Vertical component = 30 sin(-30) = -15.

So it is <25.98, -15).

The current's vector:

Horizontal component =  5 sin 20 = 1.71.

Vertical component = 5 cos 20 = 4.7.

So it is <1.71, 4.7>.

The ship's vector representing its actual motion is 30.73 mph east of north.

To solve this problem, we can break down the velocities of the ship and the water current into their horizontal and vertical components. The ship's vector can be represented as:

Ship's Vector: 30 mph at an angle of 30° south of east

Breaking this down into horizontal and vertical components:

Horizontal Component = 30 mph * cos(30°) = 25.98 mph east

Vertical Component = 30 mph * sin(30°) = 15 mph south

The water current's vector can be represented as:

Water Current's Vector: 5 mph at an angle of 20° east of north

Breaking this down into horizontal and vertical components:

Horizontal Component = 5 mph * cos(20°) = 4.75 mph north

Vertical Component = 5 mph * sin(20°) = 1.71 mph east

To find the ship's actual motion, we can add the horizontal and vertical components together:

Horizontal Component = 25.98 mph east + 4.75 mph north = 30.73 mph east of north

Vertical Component = 15 mph south + 1.71 mph east = 16.71 mph south of east

Therefore, the ship's vector representing its actual motion is 30.73 mph east of north.

Answer:

[tex]x=1/4(y-2)^{2}-1[/tex]

Step-by-step explanation:

Use Vertex form: [tex]x=a(y-k)^{2}+h[/tex]

Given: vertek (h, k)=(-1, 2)  

[tex]x=a(y-2)^2 -1[/tex]

A point:(x , y) = (3, 6)

[tex]3 = a (6-2)^{2} -1[/tex]

16a=4, a=1/4

The equation is : [tex]x=1/4(y-2)^{2}-1[/tex]

The equation for this scenario is  6b= 42.

B= 42/6= 7

The value of b that makes the equation true is 7.

Hope this helps!

Answer:

6b = 42

b = 7 for the equation to be true.

Step-by-step explanation:

If Leo has b boxes of pencils with each containing 6 pencils, it means that the total number of pencils Leo has is dependent on the number of boxes given that the number in each box is known.

The product of the number of boxes with the number in each box gives the total number of pencils Leo has. This may be expressed mathematically as

= b × 6

= 6b

Given that Leo has 42 pencils, it means that

6b = 42

Dividing both sides by 6,

b = 42/6 = 7

It means he has 7 boxes.

Answer:

Step-by-step explanation:

The train uses

[tex]\frac{400gallons}{200miles}[/tex]

If you reduce that you get that the train uses

[tex]\frac{2gallons}{1mile}[/tex]

To find the slope of the line, we will use the 2 points on the coordinate plane where the graph goes through:  (0, 0) and (400, 200)

Applying the slope formula:

[tex]m=\frac{200-0}{400-0}=\frac{1}{2}[/tex]

Answer:

6 miles per gallon

slope = 6

Step-by-step explanation:

Answer:

Part a. t = 7.29 years.

Part b. t = 27.73 years.

Part c. p = $3894.00

Step-by-step explanation:

The formula for continuous compounding is: A = p*e^(rt); where A is the amount after compounding, p is the principle, e is the mathematical constant (2.718281), r is the rate of interest, and t is the time in years.

Part a. It is given that p = $2000, r = 2.5%, and A = $2400. In this part, t is unknown. Therefore: 2400 = 2000*e^(2.5t). This implies 1.2 = e^(0.025t). Taking natural logarithm on both sides yields ln(1.2) = ln(e^(0.025t)). A logarithmic property is that the power of the logarithmic expression can be shifted on the left side of the whole expression, thus multiplying it with the expression. Therefore, ln(1.2) = 0.025t*ln(e). Since ln(e) = 1, and making t the subject gives t = ln(1.2)/0.025. This means that t = 7.29 years (rounded to the nearest 2 decimal places)!!!

Part b. It is given that p = $2000, r = 2.5%, and A = $4000. In this part, t is unknown. Therefore: 4000 = 2000*e^(2.5t). This implies 2 = e^(0.025t). Taking natural logarithm on both sides yields ln(2) = ln(e^(0.025t)). A logarithmic property is that the power of the logarithmic expression can be shifted on the left side of the whole expression, thus multiplying it with the expression. Therefore, ln(2) = 0.025t*ln(e). Since ln(e) = 1, and making t the subject gives t = ln(2)/0.025. This means that t = 27.73 years (rounded to the nearest 2 decimal places)!!!

Part c. It is given that A = $5000, r = 2.5%, and t = 10 years. In this part, p is unknown. Therefore 5000 = p*e^(0.025*10). This implies 5000 = p*e^(0.25). Making p the subject gives p = 5000/e^0.25. This means that p = $3894.00(rounded to the nearest 2 decimal places)!!!

Answer:

  B.  3y = 6

Step-by-step explanation:

(6x +5y) -(6x +2y) = (16) -(10)

6x +5y -6x -2y = 6 . . . eliminate parentheses

(6-6)x +(5-2)y = 6 . . . . add like terms

3y = 6 . . . . . . . . . . . simplify

Answer:

∠R = 36.06°, ∠Q = 90.81°

Step-by-step explanation:

I used the Law of Cosines to find angle R first.  If you use the Law of Sines, the main angle is the same, but it differs in the decimal value.  Since you started the process with the Law of Cosines, I used it again.  Setting up to find angle R:

[tex]36^2=48^2+60^2-2(48)(60)cosR[/tex] and

1296 = 2304 + 3600 - 5760cosR so

-4608 = -5700cosR and

.8084210526 = cosR

Taking the inverse cosine to find the angle,

R = 36.06

That means that Q = 180 - 36.06 - 53.13 so

Q = 90.81

Answer:

15, 18, 21, 24, 27

Step-by-step explanation:

Five multiples of 3 means we have 5 terms we are adding together to = 105.

For the sake of having something to base each one of these terms on, let's say that the first term is 3.  It's not, but 3 is a multiple of 3 and we have to start somewhere.  These terms go up by the next number that is divisible by 3.  After 3, the next number that is divisible by 3 is 6.  The next one is 9, the next is 12, the last would be 15.

Let's then say that 3 is the first term, and we are going to say that is x.

To get from 3 to 6, we add 3.  Therefore, the second term is x + 3.

To get from 3 to 9, we add 6.  Therefore, the third term is x + 6.

To get from 3 to 12, we add 9.  Therefore, the fourth term is x + 9.

To get from 3 to 15, the last term, we add 12.  Therefore, the last term is x + 12.

The sum of these terms will then be set to equal 105:

x + (x + 3) + ( x + 6) + ( x + 9) + ( x + 12) = 105

We don't need the parenthesis to simplify so we add like terms to get

5x + 30 = 105.  Subtract 30 from both sides to get

5x = 75 so

x = 15

That means that 15 is the first multiple of 3.  

The next one is found by adding 3 to the first:  so 18

The next one is found by adding 6 to the first:  so 21

The next one is found by adding 9 to the first:  so 24

The last one is found by adding 12 to the first:  so 27

15 + 18 + 21 + 24 + 27 = 105

Notice that all the numbers are, in fact, consecutive multiples of 3 as the instructions stated.

The five consecutive multiples of 3 that sum up to 105 are 15, 18, 21, 24, and 27.

The question posed is regarding five consecutive multiples of 3. The sum of these multiples equals 7x15 (or 105). Let's call the first multiple of 3 as '3x'. Therefore, the five consecutive multiples can be represented as 3x, 3x+3, 3x+6, 3x+9, 3x+12.

The sum of the five consecutive multiples then is 15x + 30 (comprising 5 times 'x', plus 30 from the sum of 3, 6, 9, and 12). We know that this sum equals 105, so we can set up the following equation:
15x + 30 = 105.

Solving this equation for 'x' gives:
x = 5. This means the first multiple is 3x, or 3x5 = 15. The next multiples are therefore 15+3 (18), 18+3 (21), 21+3 (24) and 24+3 (27).

So, the five multiples of 3 that yield a sum of 105 are 15, 18, 21, 24, and 27.

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Answer:

Depth below sea level is the independent quantity,

Water pressure is the dependent quantity

Step-by-step explanation:

An independent quantity is a variable that can be changed in an experiment. While, dependent quantity results from the independent quantity or we can say, that depends upon the independent quantity.

Here,

The water pressure increases 0.44 pounds per square inch (0.44 psi) with each increase of one foot in depth below sea level,

So, for measuring the water pressure we took depth below sea level as a variable,

⇒ Depth below sea level is the independent quantity,

While, with increasing depth by 1 foot the pressure is also increase by 0.44 pounds per square inches ⇒ pressure depends upon the depth

⇒ Water pressure is the dependent quantity.

Answer:The best answer I think is depth, water pressure

Step-by-step explanation:

Answer:

[tex]y=\frac{-4}{3}x+\frac{-4}{3}[/tex] slope-intercept form

[tex]y+4=\frac{-4}{3}(x-2)[/tex] point-slope form

Step-by-step explanation:

Equation of a line in point-slope form is y-y_1=m(x-x_1) where m is the slope and b is the [tex](x_1,y_1)[/tex] is a point on the line.

So the m, slope, can be found by calculating the rise/run from one to another point on the line.

So let's start at (2,-4) and count to (-4,4).

So the rise is 8 and the run is -6.

The slope is therefore 8/-6=-8/6=-4/3.

Now if you didn't want to count because you can't count all the time.

You could line up the two points and subtract vertically, then put 2nd difference over 1st difference.

Like this:

(  2  ,   -4)

(-4  ,      4)

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

6          -8

So the slope is -8/6=-4/3.

Anyways now using any point on the line as [tex](x_1,y_1)[/tex] along with the slope we found we can finally put into our equation for point-slope form:

[tex]y-y_1=m(x-x_1)[/tex]

with [tex](x_1,y_1)=(2,-4)[/tex] and [tex]m=\frac{-4}{3}[/tex].

This gives us:

[tex]y-(-4)=\frac{-4}{3}(x-2)[/tex]

[tex]y+4=\frac{-4}{3}(x-2)[/tex]

We probably want to put into y=mx+b form; not 100% sure so I will give you choices:

y=mx+b is called slope-intercept form because it tells us the slope is m and the y-intercept is b.

[tex]y+4=\frac{-4}{3}(x-2)[/tex]

Distribute the -4/3 to the terms inside the ( ):

[tex]y+4=\frac{-4}{3}x+\frac{8}{3}[/tex]

Subtract 4 on both sides:

[tex]y=\frac{-4}{3}x+\frac{8}{3}-4[/tex]

Simplify the (8/3)-4:

[tex]y=\frac{-4}{3}x+\frac{-4}{3}[/tex]

[tex]b[/tex] - the side of a square

[tex]a=b\sqrt2\\b=\dfrac{a}{\sqrt2}\\\\b=\dfrac{a\sqrt2}{2}[/tex]

Answer:

a√2 / 2.

Step-by-step explanation:

Using the Pythagoras Theorem;

a^2 = s^2 + s^2 where s is the length of each side of the square.

2s^2 = a^2

s^2 = a^2 / 2

s =  √(a^2 / 2)

= a / √2

= a√2 / 2 .

Answer:

Step-by-step explanation:

You must use a combination:

[tex]_nC_k=\dfrac{n!}{k!(n-k)!}[/tex]

We have n = 16, k = 3.

Substitute:

[tex]_{16}C_3=\dfrac{16!}{3!(16-3)!}=\dfrac{13!\cdot14\cdot15\cdot16}{2\cdot3\cdot13!}\qquad\text{cancel}\ 13!\\\\=\dfrac{14\cdot15\cdot16}{2\cdot3}=\dfrac{7\cdot5\cdot16}{1}=560[/tex]

The number of possible selections is 560.

The library is to be given 3 books as a gift. The books will be selected from a list of 16 titles.

Here we used the combination

[tex]= nC_n\\\\= 16C_3\\\\= \frac{16!}{3!(16-3)!}\\\\ = \frac{16!}{3!13!}\\\\ = \frac{16\times 15\times 14\times 13!}{13!3!}\\\\ = \frac{16\times 15\times 14}{3\times 2\times 1}\\[/tex]

= 560

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Answer:

  19.3%

Step-by-step explanation:

Assuming the events are independent, the probability of all five is ...

  0.72^5 ≈ 0.19349 ≈ 19.3%

Answer: 19.3%

Step-by-step explanation:

If we randomly select 5 students, we know that each of them has a probability of 72% of finding a job in that year (or 0.72 in decimal form)

The joint probability in where the 5 of them have found a job, is equal to the product of the 5 probabilities:

P = 0.72*0.72*0.72*0.72*0.72 = 0.72^5 = 0.193

Where because all the students are in the same result, the number of permutations is only one.

If we want the percentage form, we must multiplicate it by 100%, and we have that P = 19.3%

Answer:

146 degrees

Step-by-step explanation:

The measure of the arc is the measure of the central angle that the arc is created from.

The central angle has a measure of 146 degrees so that is the measure of the arc there.

Final answer:

To find the probability of selecting 5 non-defective widgets from 25 produced, we consider the independent probabilities of selecting a non-defective widget for each selection and multiply them together.Therefore, the probability of selecting 5 widgets where none are defective is 1024/3125 or approximately 0.327.

Explanation:

To find the probability of selecting 5 widgets where none are defective, we need to consider the probability of selecting a non-defective widget for each of the 5 selections.

The probability of selecting a non-defective widget from the 25 produced is (25-5)/25 = 20/25 = 4/5.

Since the selections are independent, we can multiply the probabilities. So the probability of selecting 5 non-defective widgets is (4/5)⁵ = 1024/3125.

Therefore, the probability of selecting 5 widgets where none are defective is 1024/3125 or approximately 0.327.

Answer:

  z = 2.00

Step-by-step explanation:

This is a number many statistics students memorize.

95.44% of the distribution lies within 2 standard deviations of the mean.

Answer:

z = 2.00

Step-by-step explanation:

The value of z such that "0.9544" of the area lies between −z and z rounded to two decimal places is z = 2.00.

Answer:

h=2×6/8

x^2=h^2+4

x=5/2

Answer:

224

Step-by-step explanation:

We will need the following rules for derivative:

[tex](f+g)'=f'+g'[/tex] Sum rule.

[tex](cf)'=cf'[/tex] Constant multiple rule.

[tex](x^n)'=nx^{n-1}[/tex] Power rule.

[tex](x)'=1[/tex] Slope of y=x is 1.

[tex]f(x)=12x^2+8x[/tex]

[tex]f'(x)=(12x^2+8x)'[/tex]

[tex]f'(x)=(12x^2)'+(8x)'[/tex] by sum rule.

[tex]f'(x)=12(x^2)+8(x)'[/tex] by constant multiple rule.

[tex]f'(x)=12(2x)+8(1)[/tex] by power rule.

[tex]f'(x)=24x+8[/tex]

Now we need to find the derivative function evaluated at x=9.

[tex]f'(9)=24(9)+8[/tex]

[tex]f'(9)=216+8[/tex]

[tex]f'(9)=224[/tex]

In case you wanted to use the formal definition of derivative:

[tex]f'(x)=\lim_{h \rightarrow 0} \frac{f(x+h)-f(x)}{h}[/tex]

Or the formal definition evaluated at x=a:

[tex]f'(a)=\lim_{h \rightarrow 0} \frac{f(a+h)-f(a)}{h}[/tex]

Let's use that a=9.

[tex]f'(9)=\lim_{h \rightarrow 0} \frac{f(9+h)-f(9)}{h}[/tex]

We need to find f(9+h) and f(9):

[tex]f(9+h)=12(9+h)^2+8(9+h)[/tex]

[tex]f(9+h)=12(9+h)(9+h)+72+8h[/tex]

[tex]f(9+h)=12(81+18h+h^2)+72+8h[/tex]

(used foil or the formula  (x+a)(x+a)=x^2+2ax+a^2)

[tex]f(9+h)=972+216h+12h^2+72+8h[/tex]

Combine like terms:

[tex]f(9+h)=1044+224h+12h^2[/tex]

[tex]f(9)=12(9)^2+8(9)[/tex]

[tex]f(9)=12(81)+72[/tex]

[tex]f(9)=972+72[/tex]

[tex]f(9)=1044[/tex]

Ok now back to our definition:

[tex]f'(9)=\lim_{h \rightarrow 0} \frac{f(9+h)-f(9)}{h}[/tex]

[tex]f'(9)=\lim_{h \rightarrow 0} \frac{1044+224h+12h^2-1044}{h}[/tex]

Simplify by doing 1044-1044:

[tex]f'(9)=\lim_{h \rightarrow 0} \frac{224h+12h^2}{h}[/tex]

Each term has a factor of h so divide top and bottom by h:

[tex]f'(9)=\lim_{h \rightarrow 0} \frac{224+12h}{1}[/tex]

[tex]f'(9)=\lim_{h \rightarrow 0}(224+12h)[/tex]

[tex]f'(9)=224+12(0)[/tex]

[tex]f'(9)=224+0[/tex]

[tex]f'(9)=224[/tex]

Since the number of cats has to be less than 28, a statement could be "the shelter can house no more than 28 cats.

Answer:

Possible values of c are

[tex]c=0,1,2,3,4,...,26,27[/tex]

For example: The shelter can house 17 cats because 17 < 28.

Step-by-step explanation:

Let c be the number of cats.

The given inequality is

[tex]c<28[/tex]

We need to find the possible number of cats that a shelter can house.

The number number of cats can not be

1. A fraction value

2. A Decimal value

3. A negative value

Since c<28, therefore the number of cats must be greater that or equal to 0 and less that 28.

[tex]0\leq c<28[/tex]

The possible values of c are

[tex]c=0,1,2,3,4,...,26,27[/tex]

For example: The shelter can house 17 cats because 17 < 28.

Answer:

x = 28,000

Step-by-step explanation:

"What" is our unknown, x; "is" is an equals sign; 70% expressed as a decimal is .70; "of" means to muliply.

Our equation, then, is

x = .70(40,000) so

x = 28,000

Answer:

28000

Step-by-step explanation:

70% of 40,000 is 28000.

28,000/40,000 = 70%

40000=100%

x=70%

40000/x=100%/70%

Final answer:

To find the height of the building, we use the tangent function with the angle of depression and the horizontal distance from the point to the building's base, resulting in a building height of 22 meters when rounded to the nearest meter.

Explanation:

To calculate the height of the building when the angle of depression from the top of the building to a point P on the ground is 23.6 degrees and the distance from P to the foot of the building is 50 meters, we can use trigonometry.

Specifically, we use the tangent function which relates the angle of a right triangle to the ratio of the opposite side (height of the building in this case) over the adjacent side (distance from P to the foot of the building).

Let's denote the height of the building as H. Thus, we have:

tan(23.6°) = H / 50

From this, we can solve for H:

H = 50 × tan(23.6°)

Rounding to the nearest meter, the height of the building is 22 meters.

Answer:

832

Step-by-step explanation:

standard deviation =228 minute

error =13 minute given

confidence level =905% =0.90

α=1-0.90=0.1

[tex]z_\frac{\alpha }{2}=z_\frac{0.1}{2}=1.645[/tex]

we know that sample size should be greater than

[tex]n\geq \left ( z_\frac{\alpha }{2}\times \frac{\sigma }{E} \right )^2[/tex]

[tex]n\geq \left ( 1.645\times \frac{228}{13} \right )^{2}[/tex]

[tex]n\geq 28.850^2[/tex]

[tex]n\geq 832.3668[/tex]

n=832

Answer:

Part 1) [tex]-17\frac{8}{9}[/tex] -----> [tex]-6\frac{4}{9}-3\frac{2}{9}-8\frac{2}{9}[/tex]

Part 2) [tex]-15.11[/tex] ------> [tex]-12.48-(-2.99)-5.62[/tex]

Part 3) [tex]-19\frac{8}{9}[/tex] -----> [tex]-19\frac{2}{9}-4\frac{1}{9}-(-3\frac{4}{9})[/tex]

Part 4) [tex]-201.65[/tex] -----> [tex]-353.92-(-283.56)-131.29[/tex]

Part 5) [tex]74[/tex] ------> [tex]83\frac{1}{5}-108\frac{2}{5}-(-99\frac{1}{5})[/tex]

Step-by-step explanation:

Part 1) we have

[tex]-6\frac{4}{9}-3\frac{2}{9}-8\frac{2}{9}[/tex]

To calculate the subtraction convert the mixed numbers to an improper fractions

[tex]6\frac{4}{9}=\frac{6*9+4}{9}=\frac{58}{9}[/tex]

[tex]3\frac{2}{9}=\frac{3*9+2}{9}=\frac{29}{9}[/tex]

[tex]8\frac{2}{9}=\frac{8*9+2}{9}=\frac{74}{9}[/tex]

substitute

[tex]-\frac{58}{9}-\frac{29}{9}-\frac{74}{9}=-\frac{(58+29+74)}{9}=-\frac{161}{9}[/tex]

Convert to mixed number

[tex]-\frac{161}{9}=-(\frac{153}{9}+\frac{8}{9})=-17\frac{8}{9}[/tex]

Part 2) we have

[tex]-12.48-(-2.99)-5.62[/tex]

To calculate the subtraction eliminate the parenthesis first

[tex]-12.48-(-2.99)-5.62=-12.48+2.99-5.62=-15.11[/tex]

Part 3) we have

[tex]-19\frac{2}{9}-4\frac{1}{9}-(-3\frac{4}{9})[/tex]

To calculate the subtraction convert the mixed numbers to an improper fractions

[tex]19\frac{2}{9}=\frac{19*9+2}{9}=\frac{173}{9}[/tex]

[tex]4\frac{1}{9}=\frac{4*9+1}{9}=\frac{37}{9}[/tex]

[tex]3\frac{4}{9}=\frac{3*9+4}{9}=\frac{31}{9}[/tex]

substitute

[tex]-\frac{173}{9}-\frac{37}{9}-(-\frac{31}{9})[/tex]

Eliminate the parenthesis

[tex]-\frac{173}{9}-\frac{37}{9}+\frac{31}{9}=\frac{(-173-37+31)}{9}=-\frac{179}{9}[/tex]

Convert to mixed number

[tex]-\frac{179}{9}=-(\frac{171}{9}+\frac{8}{9})=-19\frac{8}{9}[/tex]

Part 4) we have

[tex]-353.92-(-283.56)-131.29[/tex]

To calculate the subtraction eliminate the parenthesis first

[tex]-353.92+283.56-131.29=-201.65[/tex]

Part 5) we have

[tex]83\frac{1}{5}-108\frac{2}{5}-(-99\frac{1}{5})[/tex]

To calculate the subtraction convert the mixed numbers to an improper fractions

[tex]83\frac{1}{5}=\frac{83*5+1}{5}=\frac{416}{5}[/tex]

[tex]108\frac{2}{5}=\frac{108*5+2}{5}=\frac{542}{5}[/tex]

[tex]99\frac{1}{5}=\frac{99*5+1}{5}=\frac{496}{5}[/tex]

substitute

[tex]\frac{416}{5}-\frac{542}{5}-(-\frac{496}{5})[/tex]

Eliminate the parenthesis

[tex]\frac{416}{5}-\frac{542}{5}+\frac{496}{5}=\frac{(416-542+496)}{5}=\frac{370}{5}=74[/tex]

Answer:

15 miles per hour

Step-by-step explanation:

Average Speed is:

Average Speed = Total Distance/Total Time

Going uphill, she took 12 minuets, that is hours is 12/60 = 0.2 hours

We know D = RT, Distance = Rate(speed) * Time

Thus,

D = 10mph * 0.2 hr = 2 miles

So, total distance (uphill and downhill) = 2 + 2 = 4 miles

Downhill the time she took is

D = RT

2miles = 30mph * T

T = 2/30 = 1/15 hours = 1/15 * 60 = 4 minutes

Hence total time is 12 + 4 = 16 minutes

Note: 16 minutes = 16/60 = 4/15 hours

Now

Average Speed = Total Distance/Total Time

Average Speed = 4 miles/ 4/15 hours = 15 mph

Answer:

The Answer is 15.00000000000000000... miles per hour

Step-by-step explanation: You do tis by doing your work and not checking for answers

Answer:

  C.  35

Step-by-step explanation:

Let x represent the largest of the multiples of 7. The sum will be ...

  x + (x -7) + (x -14) = 84

  3x = 105 . . . . . . . . . . . . . add 21 and simplify

  x = 35 . . . . . . . . . . . . . . . divide by 3

The greatest of the numbers of interest is 35.

_____

Two consecutive multiples of 7 will differ by 7. If x is the largest, the next-largest is x-7, and the one before that is x-14.