Correct Answer - Option 2 : 12 days
Let B make 100 units / day
A make 120 units / day
Total units to be produced = A’s 1 day capacity × time taken by A
⇒ 120u × 22
⇒ 2640 u
(A + B)’s 1 day work = 220u / day
2640u will be produced in, 2640 / 220days
⇒ 12 days