A can complete a work in 20 days and B in 25 days. If they work together, the work will be completed in: MCQ with Answer and Explanation
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Question #1
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A and B together can do a piece of work in 8 days, B and C together in 12 days, and C and A together in 16 days. In how many days can A, B and C together finish the work?
Correct Answer: Option D
Explanation:
Total work = LCM(8, 12, 16) = 48 units. Efficiency of (A+B) = 6, (B+C) = 4, (C+A) = 3. Summing efficiencies gives 2 * (A+B+C) = 13, so efficiency of (A+B+C) = 13/2. Time taken = 48 / (13/2) = 96 / 13 = 7(5/13) days.
Total work = LCM(8, 12, 16) = 48 units. Efficiency of (A+B) = 6, (B+C) = 4, (C+A) = 3. Summing efficiencies gives 2 * (A+B+C) = 13, so efficiency of (A+B+C) = 13/2. Time taken = 48 / (13/2) = 96 / 13 = 7(5/13) days.
This question belongs to:
Maths
Time and Work
Question #2
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A can complete a work in 16 days and B in 32 days. After working together for 5 days, what percentage of work remains?
Correct Answer: Option B
Explanation:
Remaining work = (1 - 5*(1/16+1/32))×100 = 53.12%.
Remaining work = (1 - 5*(1/16+1/32))×100 = 53.12%.
This question belongs to:
Maths
Time and Work
Question #3
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A can complete a work in 20 days and B in 14 days. If they work together, the work will be completed in:
Correct Answer: Option D
Explanation:
Combined rate = 1/20 + 1/14. Required time = 8.24 days.
Combined rate = 1/20 + 1/14. Required time = 8.24 days.
This question belongs to:
Maths
Time and Work
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