Answer:
Area of the base = 24 cm²
Height of the prism = 5 cm
Volume of the prism = 120 cm³
F(x)= x² + 8
When x = 10
f(x) = 10² + 8 = 108
Answer: 108
We cannot calculate the confidence interval without the sample size. However, for the second question, the sample size needed would be 49.
The formula we use is

To find the z-score:
Convert 98% to a decimal: 0.98
Subtract from 1: 1-0.98 = 0.02
Divide by 2: 0.02/2 = 0.01
Subtract from 1: 1-0.01 = 0.99
Using a z-table (http://www.z-table.com) we see that this value is closest to a z-score of 2.33.
Using the z-score, our standard deviation (9) and our margin of error (3), we have:
To solve this, write a proportion of Pounds to Cost:
Pounds: 3 x
Cost: 25.50 42.50
Cross multiply 3 and 42.50, this gives you 127.5
Then, divide by 25.5
This gives you 5.
You can buy 5 pounds with $42.50