Rahul can complete a work in 12 days and Ayush in 15 days. If they work together for 3 days, then the fraction of work that will be left is:
Show answer & explanation
Correct answer: C
Explanation
The correct answer is option 3 i.e..
Let the total work to be done (LCM of 12 and 15) be 60 units.
Efficiency of Rahul = 60/12 = 5 units/day
Efficiency of Ayush = 60/15 = 4 units/day
Work done by Rahul and Ayush together in 3 days = (5 + 4) × 3 = 27 units
Remaining work = 60 - 27 = 33
Now, required fraction = 33/60 = 11/20