Solve x^2 - 4 = 77.

What is 7 / 2/3 in simplest form

galina1969 [7]

To do this we have to do 7 divided by 2/3

The first step to dividing fractions is to turn it into a mutipuacation sentence

7x2/3

Now we want to flip the second fraction over or make it a reciprocal

Our new equation is

7x 3/2 which is equal to 21/2

There are two ways. You may simplify it to 10 1/2 or just leave it as it is

hope this helped!! If you have questions, feel free to ask

4 0

2 years ago

A 15 foot flagpole casts an 11 foot shadow. At the exact same time a 28 foot tree casts a shadow. Which proportion would correct

coldgirl [10]

15/11=28/x 15x=308 308÷15=20.5 3 reapeted

8 0

3 years ago

Mrs. Jones is building wooden picture frames. She has 1 5/8 of wood and needs 3/4 for each frame. How many frames can she make w

jonny [76]

Answer:

$2\frac{1}{6}\ frames$

Step-by-step explanation:

we know that

To find out how many frames she can make with the exiting material, divide 1 5/8 by 3/4

so

$1\frac{5}{8}:\frac{3}{4}$

Convert mixed number to an improper fraction

$1\frac{5}{8}=\frac{1*8+5}{8}=\frac{13}{8}$

substitute

$\frac{13}{8}:\frac{3}{4}=\frac{52}{24}\ frames$

Simplify

$\frac{13}{6}\ frames$

Convert to mixed number

$\frac{13}{6}\ frames=\frac{12}{6}+\frac{1}{6}=2\frac{1}{6}\ frames$

6 0

3 years ago

Suppose we are interested in analyzing the weights of NFL players. We know that on average, NFL players weigh 247 pounds with a

tigry1 [53]

Answer:

$SE= \frac{\sigma}{\sqrt{n}} = \frac{47}{\sqrt{30}}= 8.58$

$ME= 1.64 *\frac{\sigma}{\sqrt{n}} = 1.64*\frac{47}{\sqrt{30}}= 14.073$

$\bar X - ME = 237- 14.073 = 222.927$

$\bar X + ME = 237+ 14.073 = 251.073$

$n=(\frac{1.640(47)}{5})^2 =237.65 \approx 238$

So the answer for this case would be n=238 rounded up to the nearest integer

Null hypothesis: $\mu \geq 247$

Alternative hypothesis: $\mu$

$z=\frac{237-247}{\frac{47}{\sqrt{30}}}=-1.165$

$p_v =P(z$

If we compare the p value and the significance level given $\alpha=0.1$ we see that $p_v>\alpha$ so we can conclude that we have enough evidence to FAIL to reject the null hypothesis, and we can't conclude that the true mean is lower than 247 at 10% of significance.

Step-by-step explanation:

For this case we have the following data given:

$\bar X =237$ represent the sample mean

$\sigma = 47$ represent the population deviation

$n =30$ represent the sample size selected

$\mu_0 = 247$ represent the value that we want to test.

The standard error for this case is given by:

$SE= \frac{\sigma}{\sqrt{n}} = \frac{47}{\sqrt{30}}= 8.58$

For the 90% confidence the value of the significance is given by $\alpha=1-0.9 = 0.1$ and $\alpha/2 = 0.05$ so we can find in the normal standard distribution a quantile that accumulates 0.05 of the area on each tail and we got:

$z_{\alpha/2}= 1.64$

And the margin of error would be:

$ME= 1.64 *\frac{\sigma}{\sqrt{n}} = 1.64*\frac{47}{\sqrt{30}}= 14.073$

The confidence interval for this case would be given by:

$\bar X - ME = 237- 14.073 = 222.927$

$\bar X + ME = 237+ 14.073 = 251.073$

The margin of error is given by this formula:

$ME=z_{\alpha/2}\frac{\sigma}{\sqrt{n}}$ (a)

And on this case we have that ME =5 and we are interested in order to find the value of n, if we solve n from equation (a) we got:

$n=(\frac{z_{\alpha/2} \sigma}{ME})^2$ (b)

Replacing into formula (b) we got:

$n=(\frac{1.640(47)}{5})^2 =237.65 \approx 238$

So the answer for this case would be n=238 rounded up to the nearest integer

State the null and alternative hypotheses.

We need to conduct a hypothesis in order to check if the true mean is lower than 247 pounds, the system of hypothesis would be:

Null hypothesis: $\mu \geq 247$

Alternative hypothesis: $\mu$

Since we know the population deviation, is better apply a z test to compare the actual mean to the reference value, and the statistic is given by:

$z=\frac{\bar X-\mu_o}{\frac{\sigma}{\sqrt{n}}}$ (1)

z-test: "Is used to compare group means. Is one of the most common tests and is used to determine if the mean is (higher, less or not equal) to an specified value".

Calculate the statistic

We can replace in formula (1) the info given like this:

$z=\frac{237-247}{\frac{47}{\sqrt{30}}}=-1.165$

P-value

Since is a left tailed test the p value would be:

$p_v =P(z$

Conclusion

If we compare the p value and the significance level given $\alpha=0.1$ we see that $p_v>\alpha$ so we can conclude that we have enough evidence to FAIL to reject the null hypothesis, and we can't conclude that the true mean is lower than 247 at 10% of significance.

5 0

3 years ago

Convert 12°34'56” to decimal degree form. Round your answer<br> to four decimal places.

Vlada [557]

Answer:

12.57555 rounded to 12.5756

Step-by-step explanation:

34'=34*1/60=0.56°

56''=56/1/3600=0.01555°

12°+0.56°+0.01555°=12.57555°

7 0

3 years ago

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