Answer: 
Step-by-step explanation:
Given : Sample size : n= 36 , which is a large sample (n>30) so the test applied here is z-test.
Significance level : 
Using Standard normal table , Critical value : 
Sample mean : 
Standard deviation: 
The confidence interval for population means is given by :-

i.e.

Hence, the 95 percent confidence interval for the fill rate = 
Answer:
the subtraction
Step-by-step explanation:
So if the 3 is on the outside of the parenthesis 3( it means you have to multiply 3 times the numbers inside the parenthesis. 3 X n+7 + 3n + 21. hope this hint helps.