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2 years ago

Dentify the percent, amount, and base in this problem. 75% of what number is 30?

Mathematics

2 answers:

anastassius [24]2 years ago

7 0

Answer:

Step-by-step explanation:

This is essentially just (4/3), or $\frac{3}{4}^{-1}$ . (4/3)*30 = 40, so our answer must be 40. Just to check, taking 75 percent of 40, we indeed get 30!

kkurt [141]2 years ago

5 0

For this case we must find a number of which 30 represents 75%. For this, we make a rule of three:

x ------------> 100%

30 ----------> 75%

Where the variable "x" determines the base number of which 30 is 75%

$x = \frac {100 * 30} {75}\\\\$

$x=40$

Thus, 30 represents 75% of 40.

Answer:

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Afina-wow [57]

Answer:

A sample size of 79 is needed.

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 $1 - \frac{\alpha}{2}$ .

For this problem, we have that:

$\pi = 0.21$

The margin of error is:

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

95% confidence level

So $\alpha = 0.05$ , z is the value of Z that has a pvalue of $1 - \frac{0.05}{2} = 0.975$ , so $Z = 1.96$ .

What sample size is needed if the research firm's goal is to estimate the current proportion of homes with a stay-at-home parent in which the father is the stay-at-home parent with a margin of error of 0.09?

A sample size of n is needed.

n is found when M = 0.09. So

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

$0.09 = 1.96\sqrt{\frac{0.21*0.79}{n}}$

$0.09\sqrt{n} = 1.96\sqrt{0.21*0.79}$

$\sqrt{n} = \frac{1.96\sqrt{0.21*0.79}}{0.09}$

$(\sqrt{n})^{2} = (\frac{1.96\sqrt{0.21*0.79}}{0.09})^{2}$

$n = 78.68$

Rounding up to the nearest whole number.

A sample size of 79 is needed.

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3 years ago

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I have no clue I just need the points have a good day tho :)

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1 year ago

Abby wants to buy one shirt for $25 and three pairs of socks for $2 per pair. If sales tax is 8%, how much will she pay in tax?

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Step-by-step explanation: you're welcome

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2 years ago

Read 2 more answers

PLEASE HELP THIS IS DUE IN AN HOUR!!!

Naily [24]

Answer:

<h2>The x-coordinate after the rotation is -10.</h2>

Step-by-step explanation:

A 810° rotation is equal to a 90° rotation. So, the transformation described gives the same result than rotating 90° only.

A 90° counterclockwise rotation is defined by the rule

$(x,y) \implies (-y,x)$

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$(8,10) \implies (-10,8)$

Therefore, the x-coordinate after the rotation is -10.

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2 years ago

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Answer:

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Step-by-step explanation:

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2 years ago