A can do a piece of work in 20 days . B is 60% more efficient than A. B can finish it in ________ days. *
Answers
Hint: Find the fraction of the total work A does in one day. Hence find the fraction of the total work B does in one day. Hence find the total number of days it takes B to finish the job. Verify your answer.
Complete step-by-step answer:
A completes one job in 12 days.
Hence the fraction of job completed by A in 1 day =112.
Since B is 60% more efficient than A, the fraction of the total job completed on one day by B will be 60% more than that of A.
Hence the fraction of the total job completed by B on one day =112+60100×112=5+360=860=215
Hence the total number of days in which B can finish the job is 1215=152=7.5
Hence B finishes the job in 7.5 days.
Hence option b is correct.
Note: Verification:
One day work of A = 112th of total work
One day work of B =17.5th=215th of total work.
Efficiency of B over A =215−112112×100=8−55×100=60
Hence B is 60% more efficient than A.
Hence our answer is verified to be correct.