A can complete a work in 10 days and B can complete the same work in 30 days. If they work together, in how many days will the work be completed? MCQ with Answer and Explanation

Explanation:
Combined rate = 1/13 + 1/33. Time = 1 ÷ combined rate = 9.33 days.

Explanation:
Let efficiency of B = 4, then efficiency of A = 5. Combined efficiency = 9 units/day. Total work = 20 * 9 = 180 units. Time taken by B alone = 180 / 4 = 45 days.

Explanation:
Total work = LCM of 12, 15, and 20 = 60 units. Efficiency of A = 5, B = 4, C = 3. Total efficiency = 5 + 4 + 3 = 12 units/day. Days required = 60 / 12 = 5 days.