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