MrBlue, from what I recall the fuel questions were a minor, extra layer on top of the S/D/T questions.
They will tell you how much fuel you have
(50 gallons) and how fast you burn through it
(25 gallons per hour) then your speed
(300 mph) and ask which of the multiple choice distance answers is the furthest you can reach
(a. 400 miles, b. 580 miles, c. 720 miles, etc).
All you have to do is first calculate the fuel
(50 gallons at 25 gallons per hour is 2 hours), then it's the same old S/D/T questions as before
(300 mph for 2 hrs means max distance of 600 miles so answer B).
My example was easy but the questions aren't too hard. They just want to see if you'll trip up with extra layers to work through.
edit: ... or they'll do it the opposite way around and give you the distance and speed then the rate of fuel consumption and ask how much fuel is needed to fly this distance.
This is just the distance divided by speed to find the time needed and then multiply the fuel consumption by the time to see how much fuel you need.
Stay chilled and good luck.
@ Crazy Voyager
I had about 5 minutes spare at the end of the cube test but I didn't need to check any of my answers
edit: "Pro" tip for the cube test. If you're sure the right answer is the first cube you look at don't waste time ruling out the others. It always seems to take me longer to work through a wrong cube and since there are 3 or 4 wrong cubes for every question then it's best to move on straight away when you find the right one.