The total fuel on the aircraft is 60 US gallons we require a reserve of
12 US gallons so this only leaves us 48 US gallons to burn.
So the question asks what is the highest consumption rate we can use if
the trip is 1 hour and 35 minutes?
Using the CRP-5 set the black triangle under the first answer which is..
Answer A is 30.3US gallons per hour
In 1hour and 35 minutes this uses 48 US gallons which is a possible
answer.
Answer B is 33.0 US gallons per hour
This answer is no use
Answer C is 37.9 US gallons per hour
Higher than B so no!
Answer D is 21.3 US gallons per hour
This will use 39 US gallons
So A looks best using all the fuel