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2 years ago

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Neo mixes 600ml of black paint with white paint in order to get grey paint. He thinks the colour came out too dark, so he decrea

ses the amount of black paint in the ratio 7:12. Calculate how much black paint it would be.

1 answer:

butalik [34]2 years ago

4 0

Answer:

the black paint is of 200 ml

Step-by-step explanation:

first he wanted grey paint by mixing 600 ml of both colour so he reduced black paint by 7:12 ratio an we get difference of 3 with that ratio so dividing 600 by 3 and we get amount of blacl paint removed

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A selective college would like to have an entering class of 950 students. Because not all students who are offered admission acc

pogonyaev

Answer:

a) The mean is 900 and the standard deviation is 15.

b) 100% probability that at least 800 students accept.

c) 0.05% probability that more than 950 will accept.

d) 94.84% probability that more than 950 will accept

Step-by-step explanation:

We use the normal approximation to the binomial to solve this question.

Binomial probability distribution

Probability of exactly x sucesses on n repeated trials, with p probability.

Can be approximated to a normal distribution, using the expected value and the standard deviation.

The expected value of the binomial distribution is:

$E(X) = np$

The standard deviation of the binomial distribution is:

$\sqrt{V(X)} = \sqrt{np(1-p)}$

Normal probability distribution

Problems of normally distributed samples can be solved using the z-score formula.

In a set with mean $\mu$ and standard deviation $\sigma$ , the zscore 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 pvalue, we get the probability that the value of the measure is greater than X.

When we are approximating a binomial distribution to a normal one, we have that $\mu = E(X)$ , $\sigma = \sqrt{V(X)}$ .

(a) What are the mean and the standard deviation of the number X of students who accept?

$n = 1200, p = 0.75$ . So

$E(X) = np = 1200*0.75 = 900$

$\sqrt{V(X)} = \sqrt{np(1-p)} = \sqrt{1200*0.75*0.25} = 15$

The mean is 900 and the standard deviation is 15.

(b) Use the Normal approximation to find the probability that at least 800 students accept.

Using continuity corrections, this is $P(X \geq 800 - 0.5) = P(X \geq 799.5)$ , which is 1 subtracted by the pvalue of Z when X = 799.5. So

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

$Z = \frac{799.5 - 900}{15}$

$Z = -6.7$

$Z = -6.7$ has a pvalue of 0.

1 - 0 = 1

100% probability that at least 800 students accept.

(c) The college does not want more than 950 students. What is the probability that more than 950 will accept?

Using continuity corrections, this is $P(X \geq 950 - 0.5) = P(X \geq 949.5)$ , which is 1 subtracted by the pvalue of Z when X = 949.5. So

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

$Z = \frac{949.5 - 900}{15}$

$Z = 3.3$

$Z = 3.3$ has a pvalue of 0.9995

1 - 0.9995 = 0.0005

0.05% probability that more than 950 will accept.

(d) If the college decides to increase the number of admission offers to 1300, what is the probability that more than 950 will accept?

Now n = 1300. So

$E(X) = np = 1300*0.75 = 975$

$\sqrt{V(X)} = \sqrt{np(1-p)} = \sqrt{1200*0.75*0.25} = 15.6$

Same logic as c.

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

$Z = \frac{949.5 - 975}{15.6}$

$Z = -1.63$

$Z = -1.63$ has a pvalue of 0.0516

1 - 0.0516 = 0.9484

94.84% probability that more than 950 will accept

5 0

2 years ago

If you have 5 blue marbles, 8 yellow marbles, and 2 green marbles. What is the probability of pulling a yellow marble?

Anika [276]

Add all them up. 5+8+2 = 15

How many yellows? 8/15 = 0.533 ~~ 53%

3 0

1 year ago

Read 2 more answers

Solve the equation. y 3 = –y 9 y = 1 y = 3 y = 6 y = 9

GaryK [48]

The solution of the equation is y = 3.

<h3>What is the linear equation?</h3>

An equation between two variables that gives a straight line when plotted on a graph.

The solution to the equation is;

$\rm y + 3 = -y + 9\\\\y+y=9-3\\\\2y=6\\\\y=\dfrac{6}{2}\\\\y=3$

Hence, the solution of the equation is y = 3.

To know more about linear equations click the link given below.

brainly.com/question/14824234

7 0

2 years ago

Solve the following systems of equations 2a+4b+c=5 ; a-4b=-6 ; 2b+c=7.

SOVA2 [1]

Answer:

a = -2

b = 1

c = 5

Step-by-step explanation:

Given:

2a + 4b + c = 5 ............(1)

a - 4b = - 6

or

a = 4b - 6 .............(2)

2b + c = 7

or

c = 7 - 2b ...........(3)

substituting 2 and 3 in 1, we get

2(4b - 6 ) + 4b + (7 - 2b) = 5

or

8b - 12 + 4b + 7 - 2b = 5

or

10b - 5 = 5

or

b = 1

substituting b in 2, we get

a = 4(1) - 6

or

a = -2

substituting b in 3, we get

c = 7 - 2(1)

or

c = 5

thus,

a = -2

b = 1

c = 5

8 0

2 years ago

Evaluate x³ for x=2.

loris [4]

Answer:

8

Step-by-step explanation:

If we have anything to the third power, we are multiplying the number by itself 3 times.

If x = 2, then the expression is $2^3$ .

$2\cdot2\cdot2=8$

Hope this helped!

7 0

3 years ago

Read 2 more answers