Answer:
0 bushels of corn 72 cars
Step-by-step explanation:
Melissa produces at the rate:
1 bushel of corn  per 8 hrs
Wash and polish a car per  2 hrs
She will wash and polish  cars  because she has the comparative advantage of requiring less time  ( 2 vs 8 hours)
Greg also will only wash and polish cars because he requires 8 hours to produce a bushel of corn vs 1 hour to wash and polish a car
Therefore  both Melissa and Greg  will wash and polish cars in the 48 hours:
Melissa will work on 24 cars since she requres 2 hours and Greg will produce 48 cars since he needs only an hour per job.
The total corn produced will be 0 bushels and  72 cars ( 24 + 48 )
