For khan academy . Need answer immediately

eimsori [14]

25x-2+3(x-4)

25x-2+3x-12
-3x on both sides

22x-2=-12
+2 on both sides

22x= -10
Divide by 22 both sides

-10/22

Then you simply giving you

Answer: 5/11

4 0

3 years ago

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For which equation is y = 7 a solution?

Natasha2012 [34]

Answer:B

Step-by-step explanation:

y - 26 = -19

y + 26 - 26 = -19 + 26

y=7

4 0

3 years ago

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5) In a certain supermarket, a sample of 60 customers who used a self-service checkout lane averaged 5.2 minutes of checkout tim

Ne4ueva [31]

Answer:

$\S^2_p =\frac{(60-1)(3.1)^2 +(72 -1)(2.8)^2}{60 +72 -2}=8.643$

$S_p=2.940$

$t=\frac{(5.2 -6.1)-(0)}{2.940\sqrt{\frac{1}{60}+\frac{1}{72}}}=-1.751$

$df=60+72-2=130$

$p_v =P(t_{130}$

Assuming a significance level of $\alpha=0.05$ we have that the p value is lower than this significance level so then we can conclude that the mean for checkout time is significantly less for people who use the self-service lane

Step-by-step explanation:

Data given

Our notation on this case :

$n_1 =60$ represent the sample size for people who used a self service

$n_2 =72$ represent the sample size for people who used a cashier

$\bar X_1 =5.2$ represent the sample mean for people who used a self service

$\bar X_2 =6.1$ represent the sample mean people who used a cashier

$s_1=3.1$ represent the sample standard deviation for people who used a self service

$s_2=2.8$ represent the sample standard deviation for people who used a cashier

Assumptions

When we have two independent samples from two normal distributions with equal variances we are assuming that

$\sigma^2_1 =\sigma^2_2 =\sigma^2$

The statistic is given by:

$t=\frac{(\bar X_1 -\bar X_2)-(\mu_{1}-\mu_2)}{S_p\sqrt{\frac{1}{n_1}+\frac{1}{n_2}}}$

And t follows a t distribution with $n_1+n_2 -2$ degrees of freedom and the pooled variance $S^2_p$ is given by this formula:

$\S^2_p =\frac{(n_1-1)S^2_1 +(n_2 -1)S^2_2}{n_1 +n_2 -2}$

System of hypothesis

Null hypothesis: $\mu_1 \geq \mu_2$

Alternative hypothesis: $\mu_1 < \mu_2$

This system is equivalent to:

Null hypothesis: $\mu_1 - \mu_2 \geq 0$

Alternative hypothesis: $\mu_1 -\mu_2 < 0$

We can find the pooled variance:

$\S^2_p =\frac{(60-1)(3.1)^2 +(72 -1)(2.8)^2}{60 +72 -2}=8.643$

And the deviation would be just the square root of the variance:

$S_p=2.940$

The statistic is given by:

$t=\frac{(5.2 -6.1)-(0)}{2.940\sqrt{\frac{1}{60}+\frac{1}{72}}}=-1.751$

The degrees of freedom are given by:

$df=60+72-2=130$

And now we can calculate the p value with:

$p_v =P(t_{130}$

Assuming a significance level of $\alpha=0.05$ we have that the p value is lower than this significance level so then we can conclude that the mean for checkout time is significantly less for people who use the self-service lane

5 0

3 years ago

What is 360 divided by 12 explain your answer

Ipatiy [6.2K]

Answer:

360 divided by 12 is 30 because 12 times 30 is 360

Step-by-step explanation:

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3 years ago

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Juanita and Samuel are planning a pizza party. They order a rectangle sheet pizza that measures 21 inches by 36 inches.?They tel

saveliy_v [14]

First, find the total area of pizza. The area of a rectangle is length times width.

Area = 21 x 36 = 756 sq. inches

Now, we must divide the total area with the largest square possible without any excess. So, we equate the area of the pizza to area of square:

A = s² = 756
s = 6 √21

Hence, the largest piece square possible has a side of 6 inches. Then, we divide the total area of the pizza by the area of each square piece to find the number of pieces;

756/6² = 21

Thus, there would be 21 pieces of 6-in square piece of pizza.

7 0

3 years ago