Question : A and B together can finish a work in 7.2 hours. If B alone can finish the same work in 18 hours, then A alone can do it in:
Option 1: 18 hours
Option 2: 12 hours
Option 3: 10 hours
Option 4: 15 hours
Correct Answer: 12 hours
Solution :
Hourly work of A and B =
Hourly work of B =
Hourly work of A =
=
=
Hence, the correct answer is 12 hours.