If you're looking for c, then the answer is 6 in. I found this answer by using a2+b2=c2 So 4 squared + 5 squared = 41. So then i found the square root of 41 which is 6.40, which rounds to 6.
Divide total price by gallons:
82.15 / 31 = 2.65 for 1 gallon
8r(40)=4
r=1/80 that is the rate for each person...
10rt=7 using r we found before
10(1/80)t=7
t/8=7
t=56 minutes.
