A and B work together. A alone can complete the work in 24 days and B alone in 22 days. What percentage of the total daily work is contributed by A? MCQ with Answer and Explanation

Explanation:
Combined rate = 1/21 + 1/25. Required time = 11.41 days.

Explanation:
Total work = LCM(15, 20) = 60 units. Efficiency of A = +4, B = -3. In 2 days (A then B), net work done = 4 - 3 = 1 unit. We need to reach 60 - 4 = 56 units first. 56 units will be done in 56 * 2 = 112 days. On the 113th day, A works and completes 4 units, making the total work 56 + 4 = 60 units. So, the wall is completed in 113 days.

Explanation:
Total work = 9 × 25 = 225 man-days. Required days = 225/13 = 17.31 days.