Write an expression equivalent to -12/27 (it is a fraction)

Use the elimination method to solve the system of equations. Choose the correct ordered pair<br>

UkoKoshka [18]

Answer:

Answer is B

Step-by-step explanation:

$12x - y = 25 \\ 9x + y = 17 \\ x = \frac{17 - y}{9} \\ 12( \frac{17 - y}{9} ) - y = 25 \\$

$\frac{204}{9} - \frac{12}{9} y - y = 25 \\ \frac{204}{9} - \frac{21y}{9} = 25 \\ - \frac{21y}{9} = 25 - \frac{204}{9} \\ - \frac{21y}{9} = 2.33 \\ - 21y = 20.997 \\ y = - 0.99$

$y = - 1 \\ x = \frac{17 - y}{9} \\ x = \frac{17 - - 1}{9} = \frac{18}{9} \\ x = 2$

5 0

3 years ago

In a survey, the planning value for the population proportion is p* = 0.35. How large a sample should be taken to provide a 95%

lions [1.4K]

Answer:

$n=\frac{0.35(1-0.35)}{(\frac{0.05}{1.96})^2}=349.59$

And rounded up we have that n=350

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".

$p$ represent the real population proportion of interest

$\aht p$ represent the estimated proportion for the sample

n is the sample size required (variable of interest)

$z$ represent the critical value for the margin of error

Solution to the problem

The population proportion have the following distribution

$p \sim N(p,\sqrt{\frac{\hat p(1-\hat p)}{n}})$

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:

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

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 $ME =\pm 0.05$ 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)

And replacing into equation (b) the values from part a we got:

$n=\frac{0.35(1-0.35)}{(\frac{0.05}{1.96})^2}=349.59$

And rounded up we have that n=350

6 0

3 years ago

I need help with percentages

satela [25.4K]

Answer:

3a. 7.2

3b. 0.9

4a. 7.2

4b. 2.4

5a. 104

5b. 260

hope this helps, everything in bold is the correct answer,

have an awesome day, -TJ

6 0

2 years ago

Read 2 more answers

Ishaan is 3 times as old as Chris and is also 14 years older than Chris. How old is ishaan?

hram777 [196]

Answer:We are also given that Ishaan is 14 years older than Christopher, so I is also 14 more than c. This gives that I = c + 14. Since I = 3c and I = c + 14, we have that 3c is equal to c + 14, giving the equation 3c = c + 14.

well this is from google and just so u know the letters stand for the names

8 0

4 years ago

I have a question if u hay that is 123 IBS and get 12ibs of anything you can thing of and get it to maybe change how it feels ho

ioda

1476 is the answer hope this helps

4 0

3 years ago