A is 50% more efficient than B. If A can complete a piece of work in 12 days, in how many days can B complete the same work? MCQ with Answer and Explanation
A can do a piece of work in 40 days. He works at it for 8 days and then B finishes it in 16 days. How long will A and B together take to complete the work?
Explanation:
Let total work be 40 units. Efficiency of A = 1 unit/day. In 8 days, A completes 8 units. Remaining work = 40 - 8 = 32 units. B finishes 32 units in 16 days, so B's efficiency = 32 / 16 = 2 units/day. Combined efficiency of A and B = 1 + 2 = 3 units/day. Time taken together = 40 / 3 = 13(1/3) days.
A, B and C can do a piece of work in 24, 30 and 40 days respectively. They began the work together but C left 4 days before the completion of the work. In how many days was the work completed?
Explanation:
Total work = LCM(24, 30, 40) = 120 units. Efficiencies: A = 5, B = 4, C = 3. Total efficiency = 12 units/day. Since C left 4 days before completion, add the work C would have done in those 4 days: 120 + (3 * 4) = 132 units. Total days = 132 / 12 = 11 days.
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