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4 years ago

What 2 numbers that are the same multiply to be 36 and add up to be 15?

1 answer:

8 0

The only way to have two numbers that are the same and add up to be 15
is if they're both 7.5 , but those don't multiply to be 36. So I guess there's
no answer that satisfies all the conditions of this question.

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Of the total population of American households, including older Americans and perhaps some not so old, 17.3% receive retirement

Alex Ar [27]

Answer:

47.54% probability that more than 20 households but fewer than 35 households receive a retirement income

Step-by-step explanation:

We use the binomial aproxiation to the normal 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 $\mu = E(X)$ , $\sigma = \sqrt{V(X)}$ .

In this problem, we have that:

$p = 0.173, n = 120$ . So

$\mu = E(X) = np = 120*0.173 = 20.76$

$\sigma = \sqrt{V(X)} = \sqrt{np(1-p)} = \sqrt{120*0.173*0.827} = 4.14$

In a random sample of 120 households, what is the probability that more than 20 households but fewer than 35 households receive a retirement income?

We are working with discrete values, so this is the pvalue of Z when X = 35-1 = 34 subtracted by the pvalue of Z when X = 20 + 1 = 21.

X = 34

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

$Z = \frac{34 - 20.76}{4.14}$

$Z = 3.2$

$Z = 3.2$ has a pvalue of 0.9993

X = 21

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

$Z = \frac{21 - 20.76}{4.14}$

$Z = 0.06$

$Z = 0.06$ has a pvalue of 0.5239

0.9993 - 0.5239 = 0.4754

47.54% probability that more than 20 households but fewer than 35 households receive a retirement income

6 0

3 years ago

A diagram of a hockey rink is shown below. The diameter of the middle circle is 30 Feet. What is the area of the middle circle?

Tatiana [17]

The formula of the area of the circle is
Area = pi * (d/2)^2

So using the formula,
Area = 3.14 * (30/2)^2
Area = 3.14 * 15^2
Area = 706.5 ft^2

So the area of the hockey rink is 706.5 ft^2

8 0

3 years ago

Which expression correctly represents “six more than the product of five and a number, decreased by one”?

Mrac [35]

(6+5n)-1

6 more than. is just adding 6 to
the product of 5 and a number, the product is multiplication, so 5*n or 5n
decreased by 1, -1

and 6+5n is in parenthesis because the addition happens before the subtraction

3 0

3 years ago

Read 2 more answers

The age of sara's father is thrice hers the age of sara's brother is 4 years more than her find an expression in terms of y for

s2008m [1.1K]

Answer:

S = 5y + 4

Step-by-step explanation:

f is Sara's father, y is Sara, b is Sara's brother and S is sum

3y = f

b = y + 4

S = f + y + b