PW: Smallest acceptable benefit

If you have an asset that costs $50 in year zero and face a MARR of 15%, what is the smallest benefit you could receive in period 15 and still find the investment acceptable?

Answer:
Did this one on the calculator using tvm solver:

N=15
I%=15
PV=-50
PMT=0

so the FV is $406.85

If the MARR was higher, the acceptable payout would also be higher.
If the MARR was lower, the acceptable payout would also be lower.