In January, Mr. Tan's students read 20 books. In February, they read 15 books.
What is the percent increase or decrease in the number of books they read?

Answer:

[tex]z(1910)=1.3429\\\\z(1230)=-0.9006\\\\z(2190)=2.2404\\\\z(1380)=-0.3558[/tex]

Step-by-step explanation:

-Given the population mean is [tex]\mu=1491[/tex]and  the standard deviation is [tex]\sigma=312[/tex], we calculate the z-scores using the formula:

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

#The z-score for 1910 can be calculated as:

[tex]z(1910)=\frac{x-\mu}{\sigma}\\\\=\frac{1910-1491}{312}\\\\=\frac{419}{312}\\\\=1.3429[/tex]

#The z-score for 1230can be calculated as:

[tex]z(1230)=\frac{x-\mu}{\sigma}\\\\=\frac{1230-1491}{312}\\\\=\frac{-281}{312}\\\\=-0.9006[/tex]

#The z-score for 2190 is calculated as follows:

[tex]z(2190)=\frac{x-\mu}{\sigma}\\\\=\frac{2190-1491}{312}\\\\=\frac{699}{312}\\\\=2.2404[/tex]

#The z-score for 1380 is calculated as:

[tex]z(1380)=\frac{x-\mu}{\sigma}\\\\=\frac{1380-1491}{312}\\\\=\frac{-111}{312}\\\\=-0.3558[/tex]

Answer:

5/2= 2 1/2 miles 2 1/2 mi x 4= 10 MPH

Step-by-step explanation:

Answer:

9.6 in an hr

Step-by-step explanation:

24 divided by 2.5

Answer:

u=10

Step-by-step explanation:

Answer

u = 10

Step-by-step explanation:

For now we do not know what u equals, but we do know that 20/5 = 4, because 20/5 simplified is just 4 since the fraction means 20 ÷ 4. Now that we are back to the question, with 2/5; if you multiply by 10 the numerator will then be 20. And now the equation is true! Hope this helps!

Answer:

  4m+3

Step-by-step explanation:

Helena had ...

  m +m +m +m +3

marbles. This is more easily written as ...

  4m +3 . . . . the number of Helena's marbles

Answer:

(a)Sample 1

The Mean = 20

The median = 25

Sample 2

The Mean = 31

The median = 60

(b) Sample 1 has the least spread

Sample 1 has the least deviations from the mean

(c) Sample 1 align with the third sample

The least representative of the population is sample 1

Step-by-step explanation:

The mean is ∑fx/∑f

∑fx = 30 + 25 + 10 + 25 + 10 = 100

∑f = 5

Mean = 100/5 = 20

For the median, we arrange the data in increasing order;

10, 10, 25, 25, 30

The median = the middle number = 25

Sample 2

The mean is ∑fx/∑f

∑fx = 5 + 60 + 10 + 30 + 50 = 155

∑f = 5

Mean = 155/5 = 31

For the median, we arrange the data in increasing order;

5, 10, 30, 50, 60

The median = the middle number = 30

(b) Sample 1 range =$30 -$10 = $20

Sample 2 range =$65 -$5 = $60

Sample 1 has the least spread

Sample 1 standard deviation = 9.354

Sample 2 standard deviation =24.083

Sample 1 has the least deviations from the mean

(c) $30, $25, $20, $20, $25

Mean = 24

$20, $20, $25, $25, $30

Median = $25

∑fx = 120

Therefore sample 1 align with the third sample

The least representative of the population is sample 1 with ∑fx = 100.

Answer:

x^2-3x-10

Step-by-step explanation:

If the zeros are -2 and 5, the equation (x+2)(x-5) is true. If you multiply those factors together you get x^2-3x-10.

here u go:

BC = 18 × 1.96

    = 35.28 ft

Therefore the distance between the pole and the tree is 35.28 ft .

Answer:

y = x + 2, assuming you need it in slope-intercept form.

Step-by-step explanation:

Isolate the y-value by dividing 2 from both sides of the equation.

Answer:I have no idea I just need points sorry lol :(

Step-by-step explanation:

Answer:

70

Step-by-step explanation:

In this problem, 27 adults conduct a survey.

In the results of the survey, it is found that 35% of the adults are concerned with poverty.

If we call:

x = number of adults surveyed

y = adults concerned with poverty

This means that we can write the following relationship:

[tex]y=0.35x[/tex] (1)

where [tex]0.35[/tex] represents the percentage of adults concerned with poverty, rewritten in decimal form ([tex]0.35=\frac{35}{100}[/tex])

Later, we are told that 200 adults are surveyed, so now we have

x = 200

So substituting into eq(1) we can find how many of these adults are concerned with poverty:

[tex]y=0.35\cdot 200 =70[/tex]

Answer:

Step-by-step explanation:150/4 = 37.5 inches small piece

                                             150 - 37.5 = 112.5 large piece

                                             37.5 * 4 = 150

Answer: the shorter piece is 30 inches long.

the longer piece is 120 inches long.

Step-by-step explanation:

Let x represent the length of the shorter piece.

Let y represent the length of the longer piece.

A 150​-inch pipe is cut into two pieces. It means that

x + y = 150- - - - - - - -1

One piece is four times the length of the other. It means that

y = 4x

Substituting y = 4x into equation 1, it becomes

x + 4x = 150

5x = 150

x = 150/5

x = 30

y = 4x = 4 × 30

y = 120

Answer:

C =12.56 inches

Step-by-step explanation:

The circumference is given by

C = 2*pi*r  where r is the radius

C = 2* 3.14 * 2

C =12.56 inches

Answer:

4π

Step-by-step explanation:

The equation for circumference is 2πr

In order to find the circumference here, plug in the given radius

2π(2) = 4π

Answer: Alex earned $87.5 more than Ben

Step-by-step explanation:

Last year,Alex earned a monthly salary of $250. This year, he received a pay increase of 25%. It means that the amount by which his pay was increased is

25/100 × 250 = 62.5

His new monthly salary would be

250 + 62.5 = $312.5

Last yearBen earned a monthly salary of $180. This year, he also received a pay increase of 25%. It means that the amount by which his pay was increased is

25/100 × 1800 = 45

His new monthly salary would be

180 + 45 = $225

The difference between the amount earned by Alex and Ben monthly is

312.5 - 225 = $87.5

Answer:

3/5

Step-by-step explanation:

Answer:

Your answer should be 3/5

Answer:

Part a) [tex]-2x(2x-5)[/tex]

Part b) [tex]3x+6[/tex]

Step-by-step explanation:

Part a)

I first determined what each piece in the rectangular array meant.

Then I wanted to figure out the height and the base length.

I know [tex]-x(x)=-x^2[/tex] so that is why I put those purple [tex]x[/tex]'s on top and purple [tex]-x[/tex]'s down alongside for the [tex]-x^2[/tex] pieces. To get [tex]x[/tex] when I already had [tex]-x[/tex], I needed to multiply by -1 which is why there is a -1 along the top where those [tex]x[/tex] pieces are.

So in the first question down the side of the box, we have [tex]-x+-x=-2x/tex].

Along the the top we have [tex]x+x-1-1-1-1-1=2x-5[/tex].

To find the area of the rectangle, you multiply height by base.

[tex]-2x(2x-5)[/tex].

Part b)We have six [tex]x^2[/tex]'s and twelve [tex]x[/tex]'s. So that means the polynomial represented here is [tex]6x^2+12x[/tex].

What happens if we divide that by [tex]2x[/tex].

Let's see:

[tex]\frac{6x^2+12x}{2x}[/tex]

[tex]\frac{6x^2}{2x}+\frac{12x}{2x}[/tex]

[tex]3x+6[/tex]

Answer:

A) 2x(2x - 5)

B) -(3x + 6)

Step-by-step explanation:

Each empty square represents: x²

Each filled rectangle represents: -x

Area is 4x² - 10x

There are two rows:

Each row is: 2x² - 5x = x(2x - 5)

Statement:

2x(2x - 5)

In b, there are 6 tiles of -x², and 12 tiles of -x, which makes it:

-6x² - 12x

-(6x² + 12x)

-(6x² + 12x)/2x

-[(6x²/2x) + (12x/2x)0

-(3x + 6)

-3x - 6

Answer: The rate at which mosquitoes are appearing in a field 15 days after the rainfall ended is -171. I believe this to be correct.

M'(15) = -171 means that after 15 days, the number of mosquitoes is decreasing at a rate of 171 mosquitoes per day.

The function M(t) represents the number of mosquitoes in a field after t days have passed since a major rainfall. The derivative of this function, M'(t), represents the rate of change of the number of mosquitoes.

M'(15) = -171 means that after 15 days, the number of mosquitoes is decreasing at a rate of 171 mosquitoes per day. In other words, the population of mosquitoes is declining by 171 mosquitoes each day.

Learn.more on rate of change : https://brainly.com/question/25184007

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Answer:

The amount the $20.000 will be worth in 17  years at compound interest is $65068.443

Step-by-step explanation:

Here we have the Principal, P = $20,000.00

The annual interest rate, r = 7% = 0.07

Time , t = 17 years

Number of compounding period per year, m = quarterly = 4

The compound interest can be found from the following formula;

[tex]Amount, \ A = P \left (1 + \frac{1}{r} \right )^{mt}[/tex]

Therefore, by plugging the values of the equation parameters, we have;

[tex]Amount, \ A = 20000 \left (1 + \frac{0.07}{4} \right )^{4 \times 17} = \$ 65068.443[/tex]

Therefore, the amount the $20.000 will be worth in 17  years at compound interest = $65068.443.

So, the amount of $20,000 be worth in 17 years if it is invested at 7% and compounded quarterly is $65068.443 and this can be determined by using the compound interest formula.

Given :

A newborn child receives a $20,000 gift toward college education from her grandparents.

The formula of compound interest is given by:

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

where A is the final amount, P is the principal amount, r is the interest rate, n is the number of times interest applied per time period and t is the number of periods elapsed.

Substitute the known terms in the above formula:

[tex]\rm A = 20000(1+\dfrac{0.07}{4})^{4\times 17}[/tex]

[tex]\rm A = 20000(1.0175)^{68}[/tex]

A = $65068.443

So, the amount of $20,000 be worth in 17 years if it is invested at 7% and compounded quarterly is $65068.443.

For more information, refer to the link given below:

https://brainly.com/question/22803385

Steph's parents need to buy 1654 meters more of fencing.

To find out how many more meters of fencing Steph's parents need to buy, let's first calculate the perimeter of the square fence.

Since all sides of a square are equal, if each side measures 666 meters, then the perimeter of the square is:

[tex]Perimeter = 4 * Side[/tex]

Given that each side measures 666 meters:

[tex]Perimeter = 4 * 666[/tex]

Now, let's calculate the total perimeter:

[tex]Perimeter = 4 * 666[/tex]

[tex]Perimeter = 2664 meters[/tex]

Now, let's see how much fencing they already have and how much more they need to buy:

[tex]Fencing already obtained = 1010 meters[/tex]

[tex]Fencing needed = Perimeter - Fencing already obtained[/tex]

[tex]Fencing needed = 2664 meters - 1010 meters[/tex]

[tex]Fencing needed = 1654 meters[/tex]

Complete correct question:

Steph needs to help her parents put a fence around their pool. They want the fence to be square and want each side to measure 666 meters. They already have 101010 meters of fencing. How many more meters of fencing should they buy?

Answer:

x=17

Step-by-step explanation:

To solve this, we can add 9 to each side of the equation. This will cancel out the 9 to only leave x by itself on one side

Once we add 9 to each side, we will be left with x=17

Answer:

May 4th, 2012.

Step-by-step explanation:

The highest level can be found with the help of the First Derivative and Second Derivative Tests. First and second derivatives of the function are, respectively:

[tex]l'(t) = 0.04323\cdot t^{2}-0.8354\cdot t +2.703[/tex]

[tex]l''(t) = 0.08646\cdot t - 0.8354[/tex]

The First Derivative Tests consists on equalizing the first derivative to zero and finding the critical points.

[tex]0.04323\cdot t^{2}-0.8354\cdot t +2.703 = 0[/tex]

Roots are [tex]t_{1} \approx 15.672[/tex] and [tex]t_{2} \approx 4.077[/tex]. just the second root offer a realistic solution and is test by the second derivative.

[tex]l''(4.077) = -0.482[/tex] (which leads to a maximum).

Given that a year has 365 days or 12 months, the highest water level occurs at day:

[tex]n = \frac{4.077}{12} \cdot (365\,days)[/tex]

[tex]n \approx 124[/tex] (May 4th).

Answer:

In accounting, residual value is another name for salvage value, the remaining value of an asset after it has been fully depreciated. The residual value derives its calculation from a base price, calculated after depreciation.

Answer:

81,3 ft to the nearest tenth.

Step-by-step explanation:

Tan 19 = 28 / h  where h = the horizontal distance.

h = 28 / tan 19

h = 81.3 ft.

Final answer:

To calculate the horizontal distance between the boat and the shark, the tangent of the angle of depression (19 degrees) is set equal to the vertical depth (28 ft) divided by the horizontal distance. The horizontal distance is found to be approximately 81.32 ft.

Explanation:

To determine the horizontal distance between the boat and the shark when the shark is swimming 28 ft below sea level and the angle of depression from the boat to the shark is 19 degrees, we can use trigonometry, specifically the tangent function. The angle of depression corresponds to the angle between the horizontal sightline from the boat and the line of sight to the shark.

In the right-angled triangle formed by the vertical depth of the shark, the horizontal distance to the shark, and the line of sight from the boat, the angle at the boat's position is 19 degrees and the opposite side (depth) is 28 ft. Using the formula tangent of an angle equals the opposite side divided by the adjacent side (tan(θ) = opposite/adjacent), we get:

tan(19°) = 28/horizontal distance

Therefore, the horizontal distance = 28 / tan(19°) = 28/0.3443

Calculating this, we get the horizontal distance to be approximately 81.32 ft.

Answer: A − 9/7

Step-by-step explanation:

Hi, to answer this question we have to convert all the numbers into decimal form.

-3 1/3 = - (3x3+1)/3 =-10/3 = - 3.3334

-4/5 = -0.8

Since he number must greater than −3 1/3 but less than − 4/5.

−3 1/3 < x < − 4/5.

- 3.3334 < x < -0.8

The correct option is A = -9/7 , because in decimal form is equal to -1.28-

- 3.3334 < -1.28 < -0.8

Answer:

2 km

Step-by-step explanation:

4π = π × r²

r² = 4

r = 2

Answer:

19 !

Step-by-step explanation: make me brainlist

Answer:

I don’t see photo

Step-by-step explanation:

I

Don’t

See

The

Photo

Answer: [tex]10m+3[/tex]

Combine Like Terms

[tex]4m+6m+3\\(4m+6m)+(3)\\10m+3[/tex]

Answer:

10m + 3

Step-by-step explanation:

You are supposed to add the like terms which are 4m and 6m to equal 10m

4m + 6m + 3

=

10m + 3

please give me brainliest

So we go up in 10's. It simply goes like this, 10,20,30,40,50,60,70,80,90,100,110,120,130,140,150,160,170,180,190,200... etc.

Answer:

   1 x 10 = 10

   2 x 10 = 20

   3 x 10 = 30

   4 x 10 = 40

   5 x 10 = 50

   6 x 10 = 60

   7 x 10 = 70

   8 x 10 = 80

   9 x 10 = 90

   10 x 10 = 100

   11 x 10 = 110

   12 x 10 = 120

Step-by-step explanation:

Answer:

See attachment

Step-by-step explanation:

A) We draw the number line as shown in the attachment with intervals of 0.2 from 0 to 2.

B) Observe that, from 0 to 0.2 you move one units to get to 0.2.

From 0 to 2, on the number line with intervals of 0.2, you move 10 units from 0.

This means that:

[tex]2 = 0.2 + 0.2 + 0.2 + 0.2 + 0.2 + 0.2 + 0.2 + 0.2 + 0.2 + 0.2[/tex]

This gives us:

[tex]2 = 0.2(1 + 1 + 1 + 1 + 1 + 1 + 1 + 1 + 1 + 1)[/tex]

Then finally we have:

[tex]2 = 0.2(10)[/tex]

By the commutative property of multiplication:

[tex]2 = 10 \times 0.2[/tex]