A, B and C can separately complete a work in 12, 15 and 20 days, respectively. They worked together for 4 days. What will be the remaining work?
Show answer & explanation
Correct answer: B
Explanation
The correct answer is option 2 i.e.
Given that
A, B and C can separately complete a work in 12, 15 and 20 days, respectively
Total work = LCM (12, 15, 20) = 120
The efficiency of A = 120/12 = 10
The efficiency of B = 120/15 = 8
The efficiency of C = 120/20 = 6
They worked together for 4 days, the work = (6 + 8 + 10) × 4 = 96
Hence, the remaining portion of the work = (120 - 96)/120 = 24/120 = 1/5