A can finish a work in 20 days. A and B can together finish a work in 12 days.Then B alone can finish the work inA24 daysB28 daysC25 daysD30 daysAnswer: D. 30 days Read Explanation: a -> 20 -> 3 a + b -> 12 - > 5 lcm(12 and 20 ) = 60 60/2 = 30 daysRead more in App