The efficiency of A, B and C is 2 : 3 : 5. A alone can complete the work in 40 days. They all worked together for 5 days and then C left the work. In how many days can A and B together complete the remaining work?
Show answer & explanation
Correct answer: D
Explanation
The correct answer is option 4 i.e. 6 days
Efficiency ratio of A : B : C = 2 : 3 : 5
A alone completes the work in 40 days
Total work = 80 units
Since A’s efficiency corresponds to 2 parts:
Efficiency of A = 80/40 = 2 units/day
Total efficiency of A + B + C = 2 + 3 + 5 = 10 units/day
Work done in 5 days = 10 × 5 = 50 units
Remaining work = 80 − 50 = 30 units
Efficiency of A + B = 2 + 3 = 5 units/day
Time taken to complete remaining work = 30/5 = 6 days
Therefore, A and B together will complete the remaining work in 6 days.