A nd B can do a work in 15 days and 10 days respectively. They begin the work together but B leaves after two days. Now A complete the remaining work. The total number of days needed for the completion of the work is:

12 days

A = 15 days, B = 10 days,

⇒ B worked for 2 days, and left = 3 x 2 = 6 units,

⇒ Remaining work is done by A since day 1 = 30 - 6 = 24 units, = \(\frac{24}{2}\) = 12 days,

⇒ Therefore, total time required to complete total work is 12 days.