A can do a work in 21 days and B in 17 days. In how many days will they complete 75% of the work together? MCQ with Answer and Explanation

Explanation:
Total work = 10 × 20 = 200 man-days. Required days = 200/14 = 14.29 days.

Explanation:
Total work = 15 × 19 = 285 man-days. Required days = 285/19 = 15.0 days.

Explanation:
Total work = LCM(24, 9, 12) = 72 units. Efficiency of A = 3, B = 8, C = 6. B and C work for 3 days: work done = 3 * (8 + 6) = 3 * 14 = 42 units. Remaining work = 72 - 42 = 30 units. Time taken by A to complete remaining work = 30 / 3 = 10 days.