B. 5
Each row across (left to right) adds up to 43
Answer:
Cost of One Journal = $3.99
Cost of One pen = $0.59
Step-by-step explanation:
Let
Cost of One Journal = x
Cost of One pen = y
We can make equation from given statements.
Mr. Bowden purchases 18 journals and 40 pencils for $95.42.

Ms. Jacinto purchases 11 journals and 16 pencils for $53.33.

Now solving these equations to find the value of x

Multiply eq(1) with 2 and eq(2) with 5

We get the value of x is: x=3.99
Now, putting value of x in equation 1 to find value of y.

So, we get the value of y: y = 0.59
Now, finding the costs:
Cost of One Journal = x = $3.99
Cost of One pen = y = $0.59
Answer:
The 90% confidence interval for the mean test score is between 77.29 and 85.71.
Step-by-step explanation:
We have the standard deviation for the sample, so we use the t-distribution to solve this question.
The first step to solve this problem is finding how many degrees of freedom, we have. This is the sample size subtracted by 1. So
df = 25 - 1 = 24
90% confidence interval
Now, we have to find a value of T, which is found looking at the t table, with 24 degrees of freedom(y-axis) and a confidence level of
. So we have T = 2.064
The margin of error is:

In which s is the standard deviation of the sample and n is the size of the sample.
The lower end of the interval is the sample mean subtracted by M. So it is 81.5 - 4.21 = 77.29
The upper end of the interval is the sample mean added to M. So it is 81.5 + 4.21 = 85.71.
The 90% confidence interval for the mean test score is between 77.29 and 85.71.
Answer:
a and b
Step-by-step explanation:
The answer for 2 is 192. The answer for 4 is 672.