Hi there RHSandLovingIt,
Much appreciate your way of solving it.
In a nutshell, its:
1- Find Distance to ETP
2 - Fond GSO and GSH
3- Time to PNR = ( Endurance in hrs * GS Home ) / GS Home + GS Out
4. Time to PNR * GS Out = Answer.
You are correct - I wonder what is the reason behind such questions but as one of the previous posters have said, some of the things that come up really make you scratch your head for the IR Ops exam.
Thanks once again.