Amar can complete a work in 15 days, and Prem, in 12 days. Starting with Amar, they work on alternate days. In how many days will the work be completed?
Show answer & explanation
Correct answer: A
Explanation
The correct answer is option 1 i.e. 13.
Given:
Amar can complete a work in 15 days
Prem can complete the same work in 12 days
Calculations:
Total work = (LCM of 15, 12) = 60 units
Efficiency of Amar = 60/15 = 4
Efficiency of Prem = 60/12 = 5
Starting with Amar, they work on alternate days
In 2 days, (4 + 5 = 9) work will be completed
In 13 days, total work completed = 9 × 6 + 4 = 54 + 4 = 58 units
The remaining work (60 - 58 = 2) will be completed by Prem in 2/5 days
Hence, the total work is completed in 13 days.