To do a certain work, the ratio of the efficiencies of A, B and C is 7 : 5 : 6. Working together, they can complete the same work in 35 days. B and C work together for 21 days. The remaining work will be completed by A alone in:
Show answer & explanation
Correct answer: B
Explanation
The correct answer is option 2 i.e. 57 days
|
Understanding |
Application |
|
A, B and C together takes 35 days. Ratio of the efficiencies of A, B and C is 7 : 5 : 6 Let the efficiencies be 7x, 5x, 6x respectively |
Total work = (7x + 5x + 6x) × 35 = 630x units |
|
B and C work together for 21 days |
Work done by B and C together in 21 days = (5x + 6x) × 21 = 231x |
|
Remaining work will be completed by A alone |
Remaining work = 630x – 231x = 399x Time taken by A = 399x/7x = 57 days |