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3 years ago

A boat propeller spins 1044 times in 3 MINUTES. Find the rate in revolutions per SECOND.

Mathematics

1 answer:

rodikova [14]3 years ago

8 0

Answer:

The answer is 5.8 times a second

Step-by-step explanation:

Divide 1044 by 180 (The number of seconds in 3 minutes)

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Twice the sum of a number and thirty-two

monitta

Answer:

2(x + 32)

Step-by-step explanation:

Let "a number" = x

Note "the sum (addition) of a number and thirty-two" = x + 32

"Twice (of the above)" (multiplication) = 2(x + 32)

2(x + 32) is your answer.

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4 years ago

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maria [59]

Yes it is correct!
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3 years ago

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Whats -5/6 divided by 3/10

enyata [817]

Answer:

-25/9

Step-by-step explanation:

-5/6 : 3/10

-->(cross multibly)

=-5 *10 : 6*3

=-50/ 18

=-25/9

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3 years ago

In the diagram below, BD is parallel to XY. What is the value of x?<br>

alexira [117]

Answer:

A. 55

Step-by-step explanation:

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3 years ago

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Nitrates are groundwater contaminants derived from fertilizer, septic tank seepage and other sewage. Nitrate poisoning is partic

o-na [289]

Answer:

a) $n=\frac{0.5(1-0.5)}{(\frac{0.02}{1.96})^2}=2401$

And rounded up we have that n=2401

b) $n=\frac{0.07(1-0.07)}{(\frac{0.02}{1.96})^2}=625.22$

And rounded up we have that n=626

And we see that if we have previous info about p the sample size varies a lot.

Step-by-step explanation:

Previous concepts

A confidence interval is "a range of values that’s likely to include a population value with a certain degree of confidence. It is often expressed a % whereby a population means lies between an upper and lower interval".

The margin of error is the range of values below and above the sample statistic in a confidence interval.

Normal distribution, is a "probability distribution that is symmetric about the mean, showing that data near the mean are more frequent in occurrence than data far from the mean".

Solution to the problem

In order to find the critical value we need to take in count that we are finding the interval for a proportion, so on this case we need to use the z distribution. Since our interval is at 95% of confidence, our significance level would be given by $\alpha=1-0.95=0.05$ and $\alpha/2 =0.025$ . And the critical value would be given by:

$z_{\alpha/2}=-1.96, z_{1-\alpha/2}=1.96$

Part a

The margin of error for the proportion interval is given by this formula:

$ME=z_{\alpha/2}\sqrt{\frac{\hat p (1-\hat p)}{n}}$ (a)

And on this case we have that $ME =\pm 0.02$ and we are interested in order to find the value of n, if we solve n from equation (a) we got:

$n=\frac{\hat p (1-\hat p)}{(\frac{ME}{z})^2}$ (b)

Since we don't have prior information about the population proportion we can use ase estimator $\hat p =0.5$ . And replacing into equation (b) the values from part a we got:

$n=\frac{0.5(1-0.5)}{(\frac{0.02}{1.96})^2}=2401$

And rounded up we have that n=2401

Part b

For thi case the estimator for p is $\hat p =0.07$

$n=\frac{0.07(1-0.07)}{(\frac{0.02}{1.96})^2}=625.22$

And rounded up we have that n=626

And we see that if we have previous info about p the sample size varies a lot.

4 0

3 years ago