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3 years ago

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(-10/9)(-9/4) both fractions are negative. I tried changing the numerators and denominators to their common factors but got stuc

k after that

1 answer:

DiKsa [7]3 years ago

5 0

2 negatives make a positive

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-6h - 13 - (-21) - 4h

bagirrra123 [75]

Answer:

-10h+8

Step-by-step explanation:

First, let's open the brackets:

-6h-13+21-4h (two -'s make a +)

This is equal to -10h + 8

8 0

3 years ago

Read 2 more answers

Reading proficiency: An educator wants to construct a 99.5% confidence interval for the proportion of elementary school children

Shkiper50 [21]

Answer:

A sample size of 345 is needed so that the confidence interval will have a margin of error of 0.07

Step-by-step explanation:

In a sample with a number n of people surveyed with a probability of a success of $\pi$ , and a confidence level of $1-\alpha$ , we have the following confidence interval of proportions.

$\pi \pm z\sqrt{\frac{\pi(1-\pi)}{n}}$

In which

z is the zscore that has a pvalue of $1 - \frac{\alpha}{2}$ .

The margin of error of the interval is given by:

$M = z\sqrt{\frac{\pi(1-\pi)}{n}}$

In this problem, we have that:

$p = 0.69$

99.5% confidence level

So $\alpha = 0.005$ , z is the value of Z that has a pvalue of $1 - \frac{0.005}{2} = 0.9975$ , so $Z = 2.81$ .

Using this estimate, what sample size is needed so that the confidence interval will have a margin of error of 0.07?

This is n when M = 0.07. So

$M = z\sqrt{\frac{\pi(1-\pi)}{n}}$

$0.07 = 2.81\sqrt{\frac{0.69*0.31}{n}}$

$0.07\sqrt{n} = 1.2996$

$\sqrt{n} = \frac{1.2996}{0.07}$

$\sqrt{n} = 18.5658$

$(\sqrt{n})^{2} = (18.5658)^{2}$

$n = 345$

A sample size of 345 is needed so that the confidence interval will have a margin of error of 0.07

4 0

3 years ago

Cody was 165\,\text{cm}165cm165, space, c, m tall on the first day of school this year, which was 10\%10%10, percent taller than

earnstyle [38]

Assume that Cody was x cm tall on his first day at school last year.
Assume that Cody is y cm tall on his first day at school this year.
This year, Cody became 10% taller.
10% is equivalent to 0.1

This can be translated into the following:
y = x + 0.1x
We are given that y = 165 cm.
Substitute in the equation to get x as follows:
165 = x + 0.1x
165 = 1.1x
x = 150 cm

Based on the above calculations, Cody was 150 cm tall on his first day at school last year.

4 0

3 years ago

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Use the function below to find F(4).

Alexxx [7]

Answer:

A. 81

Step-by-step explanation:

F(x)= $3^{x}$

if x=4, then F(4) = $3^{4}$ = 3×3×3×3=81

7 0

1 year ago

7TH GRADE MATH NEED ASAPP

Illusion [34]

I believe it is A because 3p has to be equal to or greater than 45

4 0

3 years ago

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