Question about net benefit for economics class?

Question

Jim's truck is almost out of gas. He can fill it up for $50 at the Shell station. At the Chevron station across the street, he can fill-up for $45, but it will take 15 minutes longer because of the waiting line. Jim values his time at $40 per hour. For Jim, the net benefit of filling-up at the Chevron station equals $_____.

-My guess is -5 dollars

Someone help?

Answer 1

...once again proving that economics is not a science.

Answer 2

Cost of Shell: $50

Cost of Chevron: $45 + $40*1/4=$55

The net benefit of filling up at Chevron is -$5; it's better to fill up at the Shell.