Which choice shows the product of 23 and 39? 23 39=6223 39=62 (23)(39)=897(23)(39)=897 23×39=67723×39=677 23⋅39=77723⋅39=777

What is the answer to this question

astra-53 [7]

Answer: I think the answer is B

Step-by-step explanation:

8 0

3 years ago

Solve each proportion, round to one decimal place.<br> 4/9=x/20

guapka [62]

In order to solve a proportion you need to cross multiply, so you would do:

4x20 and 9xX and you would get...

9x=80

then divide by nine to get

x=8.8888888889

which is technically 8.9

3 0

3 years ago

Suppose a local manufacturing company claims their production line has a variance of less than 9.0. A quality control engineer d

Alexxx [7]

Answer:

$\chi^2 =\frac{35-1}{9} 2.12^2 =16.979$

$p_v =P(\chi^2$

If we compare the p value and the significance level provided we see that $p_v$ so on this case we have enough evidence in order to reject the null hypothesis at the significance level provided. And that means that the population variance is significantly lower than 9

Step-by-step explanation:

Notation and previous concepts

A chi-square test is "used to test if the variance of a population is equal to a specified value. This test can be either a two-sided test or a one-sided test. The two-sided version tests against the alternative that the true variance is either less than or greater than the specified value"

$n=35$ represent the sample size

$\alpha=0.01$ represent the confidence level

$s =2.12$ represent the sample deviation obtained

$\sigma_0 =3$ represent the value that we want to test

Null and alternative hypothesis

On this case we want to check if the population variance specification is lower than 9 and the deviation lower than 3, so the system of hypothesis would be:

Null Hypothesis: $\sigma^2 \geq 9$

Alternative hypothesis: $\sigma^2$

Calculate the statistic

For this test we can use the following statistic:

$\chi^2 =\frac{n-1}{\sigma^2_0} s^2$

And this statistic is distributed chi square with n-1 degrees of freedom. We have eveything to replace.

$\chi^2 =\frac{35-1}{9} 2.12^2 =16.979$

Calculate the p value

In order to calculate the p value we need to have in count the degrees of freedom , on this case df= n-1= 35-1=34. And since is a left tailed test the p value would be given by:

$p_v =P(\chi^2$

In order to find the p value we can use the following code in excel:

"=CHISQ.DIST(16.979,34,TRUE)"

Conclusion

If we compare the p value and the significance level provided we see that $p_v$ so on this case we have enough evidence in order to reject the null hypothesis at the significance level provided. And that means that the population variance is significantly lower than 9

6 0

4 years ago

It takes 1/3 of an hour to take down 1/9 of the camp at the YMCA campground. How long does it take the camp staff to take down t

I am Lyosha [343]

Answer:

Step-by-step explanation:

1/9 of the camp means it has 9 parts the whole thing (each 1/9)

1/3 of an hour for 1 part and

for 9 parts we have

1/3 *9 = 9/3= 3 hours

7 0

3 years ago

Altred is saving up money for a down payment on a house. He currently has $4739, but knows he can get a loan at a lower interest

Stella [2.4K]

Given the word problem, we can deduce the following information:

Principal amount = $4739

Future amount = $5336

Interest = 5.1 % =0.051

To determine the time to accumulate the $5336, we use the compound interest formula:

$A=P(1+\frac{r}{n})^{nt}$

A=Future amount=$5336

P=Present amount=$4739

r=interest rate = 0.051

n=number of compounding periods =12

t=time in years

We also note that the number of compounding periods must be 12 since the investment is compounded monthly.

We plug in what we know:

$\begin{gathered} A=P(1+\frac{r}{n})^{nt} \\ 5336=4739(1+\frac{0.051}{12})^{12t} \\ Simplify\text{ and rearrange} \\ 5336=4739(\frac{12.051}{12})^{12t} \\ 12t=\frac{\ln\frac{5336}{4739}}{\ln\frac{12.051}{12}} \\ t=\frac{\operatorname{\ln}\frac{5,336}{4,739}}{12\operatorname{\ln}\frac{12.051}{12}} \\ Calculate \\ t=2.33 \end{gathered}$

Therefore, the answer is 2.33 years.

5 0

1 year ago