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zloy xaker [14]
3 years ago
15

8. Number of boys in a class is twice the number of girls. 20% of the girls are brunettes and of the rest – half are blondes: Ma

ry, Clara, Gina and Trisha. How many boys study in this class?
Mathematics
1 answer:
slega [8]3 years ago
8 0

Answer:

<em>20 boys </em>

Step-by-step explanation:

b = 2g

100% - 20% = 80%

80% ÷ 2 = 40% = 0.4

0.4g = 4 ⇒ g = 4 ÷ 0.4 = 10

b = 2 × 10 = 20

There are 10girls and <em>20 boys</em> study in the class.

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Find the area bounded by the graphs of the indicated equations over the given interval.
NeX [460]

Answer:

48

Step-by-step explanation:

y = 0

is basically the horizontal axis.

First, find the integral of x^2-25.

Remember that

integral of a constant is that constant times x.

Also that

to take the integral of a power function, add 1 to the degree and divide by that same degree.

y =  {x}^{2}  - 25

We then get

\frac{ {x}^{3} }{3}  - 25x

Evaluate at -3

\frac{ - 3 {}^{3} }{3}  - 25( - 3)

- 27 + 75 = 48

Then we evaluate at 0

\frac{0 {}^{3} }{3}  - 25(0) = 0

Next, we subtract the the answer then we get

48 - 0 = 48

8 0
2 years ago
Two polygons are similar with the longest side of one 8 and the longest side of the other 10. Find the ratio of the areas.
liubo4ka [24]
<span>The ratio of sides is, 8:10 = 4:5
squaring it yields, 16:25 
the ratio of the area is 16:25

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7 0
3 years ago
Read 2 more answers
3/4 Tones = __ lb????<br><br> HELP ASAP <br><br> Thank you
Shtirlitz [24]
The answer is 1500 pound because 1 ton = 2,000 pounds. 1/4 of a ton = 500 pounds. So 3/4 tons = 500*3 =1500 pounds.
6 0
3 years ago
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Evaluate the expression if a = 5, b = 12 and c = 4.
Natalija [7]

3 because 2*12 24 24/8 is 3 hope this helps

4 0
3 years ago
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VMariaS [17]

Answer:

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Step-by-step explanation:

Given:

μ = true average radioactivity level(picocuries per liter)

5 pCi/L = dividing line between safe and unsafe water

The recommended test here is to test the null hypothesis, H0: μ = 5 against the alternative hypothesis Ha: μ < 5.

A type I error, is an error where the null hypothesis, H0 is rejected when it is true.

We know type I error can be controlled, so safer option which is to test H0: μ = 5 vs Ha: μ < 5 is recommended.

Here, a type I error involves declaring the water is safe when it is not safe. A test which ensures that this error is highly unlikely is desirable because this is a very serious error. We prefer that the most serious error be a type I error because it can be explicitly controlled.

7 0
2 years ago
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