A can complete a task in 10 days and, B can finish a task in 15 days respectively. A starts the work and works for 4 days, after which B joins A. How many more days will they take to complete the task?
Show answer & explanation
Correct answer: A
Explanation
A's rate = 1/10
B's rate = 1/15
Work done by A in 4 days = 4 × 1/10 = 2/5
Remaining work = 1 − 2/5 = 3/5
(A + B)'s rate = 1/10 + 1/15 = 1/6
Time = (3/5) ÷ (1/6) = 3.6 days