A and B can complete a work in 15 days and 10 days respectively

• Time Work

A and B can complete a work in 15 days and 10 days respectively. They started doing the work together but after 2 days B had to leave and A alone completed the remaining work. The whole work was completed in:

1. 8 days
2. 10 days
3. 12 days
4. 15 days

Answer

Let total work be 30 units (LCM of 10 and 15).

In one day, A can do 2 units of work and B can do 3 units of work.

In one day, both A and B can do 5 units of work.

In two days, A and B will complete 10 units of work. Remaining 20 units can be completed by A in 10 days (at rate of 2 units per day).

Hence, whole work will be completed in 12 days.

The correct option is C.