If y varies with x, and y equals 10 when x equals 4, find when y equals 80

The friendly old woman sold 38 long-

dem82 [27]

Answer:

Step-by-step eWrite 2.9 as

2.9

1

Multiply both numerator and denominator by 10 for every number after the decimal point

2.9 × 10

1 × 10

=

29

10

Reducing the fraction gives

29

10xplanation:

3 0

3 years ago

You need to buy enough sand to fill a sandbox to the top. The sandbox is modeled by the right rectangular prism in the diagram.

kifflom [539]

Answer:80

Step-by-step explanation:

Mutiply all

4 0

3 years ago

5x=3x+20 can you answer this and show how you got the answer

charle [14.2K]

5x=3x+20
5x-3x=3x-3x+20
2x=20
2x/2=20/2
X=10 Hope this helped!

-Twix

8 0

3 years ago

Read 2 more answers

ASAP will give brainliest show work check out the photo

gtnhenbr [62]

Answer:

what do you want me to do there's no question

Step-by-step explanation:

4 0

3 years ago

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