A can complete a work in 60 days. B is 25% more efficient than A. They work together for 15 days. C alone completes the remaining work in 14 days. B and C together will complete th part of the original work in:
Show answer & explanation
Correct answer: D
Explanation
The correct answer is option 4 i.e. 12 days.
Let the efficiency of A = 4 units/ day
Total work = 4 × 60 = 240 units
The efficiency of B = 125% of 4 = 5 units/day
Both A and B work for 15 days
Work done by A and B in 15 days = 15 × 9 = 135 units
Remaining work = 240 - 135 = 105 units
The efficiency of C = 105/14 = 7.5 units/day
5/8 of the work = 5/8 × 240 = 150 units
Time taken by B and C to finish 150 units of work = 150/12.5 = 12 days