A and B can finish a piece of work in 24 days and 32 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?

12

Total work = efficiency × number of days

Work done by A in 3 days = 4 × 3 = 12

Remaining work = 96  - 12 = 84

Total efficiency of A and B = 3 + 4 = 7

Time taken when A & B worked together  = \(\frac{84}{7}\) = 12 days

Hence, B left the work after 12 days