A can complete a work in 13 days and B can complete the same work in 33 days. If they work together, in how many days will the work be completed? MCQ with Answer and Explanation
A and B can complete a work in 12 days and 16 days respectively. Both work together for 3 days and then A leaves. How long will B take to complete the remaining work?
Explanation:
Total work = LCM(12, 16) = 48 units. Efficiency of A = 4, B = 3. Combined efficiency = 7 units/day. In 3 days, work completed = 3 * 7 = 21 units. Remaining work = 48 - 21 = 27 units. Time taken by B to complete remaining work = 27 / 3 = 9 days.
Explanation:
Combined 1-day work = 1/6. A's 1-day work = 1/18. B's 1-day work = 1/6 - 1/18 = 2/18 = 1/9. Therefore, B alone can complete the work in 9 days.
A, B and C can complete a piece of work in 10, 12 and 15 days respectively. They started together but A left 2 days after the start and B left 3 days before the completion of the work. How long did the work last?
Explanation:
Total work = LCM(10, 12, 15) = 60 units. Efficiency of A = 6, B = 5, C = 4. Let total days be x. A works for 2 days. B works for (x - 3) days. C works for x days. Total work = 2*6 + (x - 3)*5 + 4*x = 60 => 12 + 5x - 15 + 4x = 60 => 9x - 3 = 60 => 9x = 63 => x = 7 days.
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