All categories

3 years ago

(10 POINTS AND BRAINLIEST FOR BEST)

Mathematics

1 answer:

Juli2301 [7.4K]3 years ago

6 0

Answer:

Step-by-step explanation:

14+Sale tax=14.98

14.98-14=sale tax

14.98-14=0.98

0.98 is the sale tax now we need to find the percent

Let represent t percent

14 of t%=0.98

14*t/100=0.98

we need to use inverse operation to isolate T on one side so if its multiplication we need to do division on both sides to un-due multiplication.

So to move 100 we need to multiply on both sides and we will get

14*t=0.98*100

0.98*100=98

14*t=98

to move 14 we need to divide

14/14=1

we dont need to put 1t becuase t is =1

so we just write it as t

98/14=7

t=7

so Sale tax percent is 7%

You might be interested in

Solve the equation-2/3x = -12 show work plz

Lorico [155]

Answer:

Step-by-step explanation:

-2/3x = -12

-2 = 3x × -12

-2 = -36x

2 = 36x

2/36 = x

1/18 = x

3 0

2 years ago

Read 2 more answers

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: