A, B and C can complete a piece of work in 10, 12 and 15 days respectively. A left the work 5 days before the work was completed and B left 2 days after A had left. Number of days required to complete the whole work was:
Solution
Answer (D): 7 days
Explanation:
The answer is exact 7 days.
A leaves 5 days before completion of work.
B leaves 2 days after A.
It means, C has worked alone for 3 days to complete the job.
Now C does the entire work in 15 days.
So, C will finish (1/5)th or 20% of the total work in 3 days.
So, before both A & B had left, 80% work was already done.
Now, it's mentioned that B has left 2 days after A. This means that B & C have worked together for 2 days.
For (B+C) as a team, they finish (9/60) part of the work in 1 day. So, in 2 days, they would have finished (18/60) parts of the total job. THIS figure when converted to % yields 30%.
18/60 = 3/10.
So, 30% work is done by (B+C) team.
So,(A+B+C) team completes 50% of the work for which they take 2 days full.
So, 2+2+3 = 7 days.
Answer (D): 7 days
Explanation:
The answer is exact 7 days.
A leaves 5 days before completion of work.
B leaves 2 days after A.
It means, C has worked alone for 3 days to complete the job.
Now C does the entire work in 15 days.
So, C will finish (1/5)th or 20% of the total work in 3 days.
So, before both A & B had left, 80% work was already done.
Now, it's mentioned that B has left 2 days after A. This means that B & C have worked together for 2 days.
For (B+C) as a team, they finish (9/60) part of the work in 1 day. So, in 2 days, they would have finished (18/60) parts of the total job. THIS figure when converted to % yields 30%.
18/60 = 3/10.
So, 30% work is done by (B+C) team.
So,(A+B+C) team completes 50% of the work for which they take 2 days full.
So, 2+2+3 = 7 days.