A and B can complete a work in 10 and 12 days respectively. A and B start working together and after 4 days, A left the work. Find in how many days work will be completed.

7\(\frac{1}{5}\)

Total work = Efficiency × Number of days

Work done by ( A + B ) in 4 days = 11 × 4 = 44

Remaining work = 60 - 44 = 16

Time taken by B to complete the remaining work = \(\frac{16}{5}\)

= 3\(\frac{1}{5}\)

Total time taken in doing whole work = 4 + 3\(\frac{1}{5}\)

= 7\(\frac{1}{5}\)  days