A sorry I can't see the image
Answer: 37
Step-by-step explanation:
Given : Significance level : 
Critical value : 
margin of error : E= 1 mile per gallon
Population standard deviation:
miles per gallon.
We know that when the population standard deviation is known then the formula to find the sample size is given by :

[Round to the next whole number.]
Hence, the required number of automobiles should be used in the test = 37
5 gerbils = p dollars
1 gerbil = p/5 dollars
g gerbils = pg / 5 dollars
5/p gerbils = 1 dollar
5d/p gerbils = d dollars