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3 years ago

I need help with my math!

Mathematics

1 answer:

pantera1 [17]3 years ago

3 0

Answer:

there are a total of 20 boys and 30 girls in the choir of 50 students

Step-by-step explanation:

Scale the ratio 2:3. so that the numbers on either side sum to 50 . 2+3=5 , and 50÷5=10 , so we scale our ratio by a factor of 10 . So there are a total of 20 boys and 30 girls in the choir of 50 students

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Can someone help me find the diameter? also what is a diameter even?

lukranit [14]

Answer:

Step-by-step explanation:

area of circle = πr²

πr² = 144π

Cancel out π

r² = 144

r = √144

r = 12

diameter = 2 x radius

diameter = 2 x 12

diameter = 24m

* diameter is the "width of a circle", the distance from the widest points of the circle

3 0

2 years ago

Thomas has $6.35 in dimes and quarters. The number of dimes is three more than three times the number of quarters. How many quar

mr Goodwill [35]

Answer:

He has 11 quarters

Step-by-step explanation:

* Lets study the information in the problem to solve it

- The value of dimes and quarters is $6.35

- There are dimes and quarters

- The dime = 10 cents

- The quarter = 25 cents

* We must change the money from dollars to cents

∵ $1 = 100 cents

∴ $6.35 = 6.35 × 100 = 635 cents

- The number of dimes = 3 + 3 × number of quarters

* Let number of dimes is D and number of quarter is Q

∴ D = 3 + 3Q

∴ 10D + 25Q = 635

* Substitute the value of D from first equation in the second equation

∴ 10(3 + 3Q) + 25Q = 635 ⇒ open the bracket

∴ 10(3) + 10(3Q) + 25Q = 635

∴ 30 + 30Q + 25Q = 635 ⇒ collect like terms

∴ 30 + 55Q = 635 ⇒ subtract 30 from both sides

∴ 55Q = 605 ⇒ divide both sides by 55

∴ Q = 11

* He has 11 quarters

5 0

3 years ago

An art history professor assigns letter grades on a test according to the following scheme. A: Top 13% of scores B: Scores below

madam [21]

Answer:

The numerical limits for a B grade are 81 and 89, that is, a score between 81 and 89 gets a B grade.

Step-by-step explanation:

Normal Probability Distribution:

Problems of normal distributions can be solved using the z-score formula.

In a set with mean $\mu$ and standard deviation $\sigma$ , the z-score of a measure X is given by:

$Z = \frac{X - \mu}{\sigma}$

The Z-score measures how many standard deviations the measure is from the mean. After finding the Z-score, we look at the z-score table and find the p-value associated with this z-score. This p-value is the probability that the value of the measure is smaller than X, that is, the percentile of X. Subtracting 1 by the p-value, we get the probability that the value of the measure is greater than X.

Scores on the test are normally distributed with a mean of 79.7 and a standard deviation of 8.4.

This means that $\mu = 79.7, \sigma = 8.4$

B: Scores below the top 13% and above the bottom 56%

So between the 56th percentile and the 100 - 13 = 87th percentile.

56th percentile:

X when Z has a p-value of 0.56, so X when Z = 0.15. Then

$Z = \frac{X - \mu}{\sigma}$

$0.15 = \frac{X - 79.7}{8.4}$

$X - 79.7 = 0.15*8.4$

$X = 81$

87th percentile:

X when Z has a p-value of 0.87, so X when Z = 1.13.

$Z = \frac{X - \mu}{\sigma}$

$1.13 = \frac{X - 79.7}{8.4}$

$X - 79.7 = 1.13*8.4$

$X = 89$

The numerical limits for a B grade are 81 and 89, that is, a score between 81 and 89 gets a B grade.

4 0

3 years ago

How do you get 25 for the order of operations

mojhsa [17]

PEMDAS Solve the parentheses first so 9+4=13. Then do the division so 6/6=1. Now the equation is 37- 13+ 1. Then work left to right. 37-13= 24 then 24+1=25.

5 0

3 years ago

-3w-3x-7w+4x-2w ......

valkas [14]

Answer:

− 1 2 +

Step-by-step explanation:

3 0

3 years ago

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