A can do 20% of a work in 4 days, and B can do 33% of the same work in 10 days. They worked together for 9 days and then C completed the remaining work in 6 days. B and C together will complete 75% of the same work in:
Show answer & explanation
Correct answer: D
Explanation
The correct answer is option 4 i.e. 10 days.
A can do 20% of the work in 4 days.
Therefore,
A's work rate = = 5% per day
B can do (33.33%) of the work in 10 days.
Therefore,
B's work rate = = 3.33% per day
the work done by A and B together in 9 days:
Combined work rate= 5% + 3.33% = 8.33% per day
Work done in 9 days = 8.33% × 9 = 75%
Remaining work = 100% − 75% = 25%
C completed the remaining 25% of the work in 6 days.
Therefore,
C's work rate per day is:
C’s work rate = 25%/6 ≈ 4.17% per day
the time taken by B and C together to complete 75% of the work rate = 3.33% + 4.17% = 7.5% per day
Time = =10days