A and B can finish a piece of work in 18 days and 27 days respectively. Together they start the work but after few days B left the job. After how many days had B left the job if A finished the remaining work in 3 days?

9

Total work = efficiency × number of days

Work done by A in 3 days = 3 × 3 = 9

Remaining work = 54 - 9 = 45

Total efficiency of A and B = 2 + 3 = 5

Time taken when A & B worked together  = \(\frac{45}{5}\) = 9 days

Hence, B left the work after 9 days