A can complete a work in 26 days and B in 42 days. If both work together, in how many days will the work be completed? MCQ with Answer and Explanation
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Question #1
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A can complete a work in 16 days and B in 21 days. If they work together, the work will be completed in:
Correct Answer: Option A
Explanation:
Combined rate = 1/16 + 1/21. Required time = 9.08 days.
Combined rate = 1/16 + 1/21. Required time = 9.08 days.
This question belongs to:
Maths
Time and Work
Question #2
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A and B can do a work in 8 days, B and C in 12 days and A, B, C together in 6 days. In how many days can A and C together complete the work?
Correct Answer: Option D
Explanation:
Total work = LCM(8, 12, 6) = 24 units. Efficiency of (A+B) = 3, (B+C) = 2, (A+B+C) = 4. Efficiency of C = (A+B+C) - (A+B) = 4 - 3 = 1. Efficiency of A = (A+B+C) - (B+C) = 4 - 2 = 2. Combined efficiency of A and C = 2 + 1 = 3. Time taken by A and C together = 24 / 3 = 8 days.
Total work = LCM(8, 12, 6) = 24 units. Efficiency of (A+B) = 3, (B+C) = 2, (A+B+C) = 4. Efficiency of C = (A+B+C) - (A+B) = 4 - 3 = 1. Efficiency of A = (A+B+C) - (B+C) = 4 - 2 = 2. Combined efficiency of A and C = 2 + 1 = 3. Time taken by A and C together = 24 / 3 = 8 days.
This question belongs to:
Maths
Time and Work
Question #3
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A can complete a work in 24 days and B can complete the same work in 24 days. If they work together, in how many days will the work be completed?
Correct Answer: Option C
Explanation:
Combined rate = 1/24 + 1/24. Time = 1 รท combined rate = 12.0 days.
Combined rate = 1/24 + 1/24. Time = 1 รท combined rate = 12.0 days.
This question belongs to:
Maths
Time and Work
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