A can do a piece of work in 25 days. After working for 5 days, he took help of B and completed the work in 8 days. If both A and B had worked together from the beginning, in how many days would they have completed the work?
Show answer & explanation
Correct answer: C
Explanation
The correct answer is Option 3 i.e. 10.
Work done by A in 1 day = 1/25
Let the work done by B in 1 day = 1/x
Work done by A in 5 days = 5/25 = 1/5
Remaining work = 1 - 1/5 = 4/5
A and B together completed the remaining work (4/5) in 8 days
⇒ Work done by A and B together in 1 day = 4/5 ÷ 8 = 1/10
So, they complete the work in 10 days.