A can finish a work in 60 days. He works at it for 15 days and then B alone finishes the remaining work in 48 days. In how much time can A and B working together finish the work?
Show answer & explanation
Correct answer: A
Explanation
The correct answer is option 1 i.e. days.
A's work rate = 1/60 work/day
Work done by A in 15 days = (1/60) × 15 = 1/4
Remaining work = 1 - (1/4) = 3/4
B's work rate = (3/4)/48 = 1/64 work/day
Combined work rate of A and B = 1/60 + 1/64 = 31/960 work/day
Time required for A and B = 1/(31/960) = 960/31 days
Therefore, A and B working together can finish the work in 960/31 days.