The answer is 8.5h
Terry 10h
Jill 10(1.0 - 0.20)h
Jerry 10(1.0 - 0.20)h + 0.50h
thus, Jerry earns
10(1.0 - 0.20)h + 0.50h
10(0.80)h + 0.50h
8h + 0.50h
8.5h
9.5m questions
12.2m answers