Example sim question:
Fuel Flow per engine is xxxxx
You have xxxxxx fuel Remaining
Whats your d from ABC vor when you run out?
So, find endurance, estimate TAS/IAS, take wind into account, therefore work out groundspeed, with endurance work out distance covered, convert that to distance from ABC vor.
OUCH........
......all while navigating and flying a jet youve never flown before....