A can complete a work in 21 days and B in 17 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 is 40% more efficient than B. If they together can finish a work in 10 days, in how many days can A alone finish it?
Correct Answer: Option C
Explanation:
Let efficiency of B = 5, then efficiency of A = 7. Combined efficiency = 12 units/day. Total work = 10 * 12 = 120 units. Time taken by A alone = 120 / 7 = 17(1/7) days.
Let efficiency of B = 5, then efficiency of A = 7. Combined efficiency = 12 units/day. Total work = 10 * 12 = 120 units. Time taken by A alone = 120 / 7 = 17(1/7) days.
This question belongs to:
Maths
Time and Work
Question #2
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A group of men decided to do a work in 10 days, but 5 of them became absent. If the rest of the group did the work in 12 days, find the original number of men.
Correct Answer: Option A
Explanation:
Let the original number of men be x. Using M1 * D1 = M2 * D2: x * 10 = (x - 5) * 12 => 10x = 12x - 60 => 2x = 60 => x = 30.
Let the original number of men be x. Using M1 * D1 = M2 * D2: x * 10 = (x - 5) * 12 => 10x = 12x - 60 => 2x = 60 => x = 30.
This question belongs to:
Maths
Time and Work
Question #3
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A and B can do a piece of work in 12 days, B and C in 15 days, and C and A in 20 days. In how many days will A, B, and C finish it working together?
Correct Answer: Option A
Explanation:
2(A + B + C)'s 1-day work = 1/12 + 1/15 + 1/20 = 12/60 = 1/5. Therefore, (A + B + C)'s 1-day work = 1/10. Working together, they finish in 10 days.
2(A + B + C)'s 1-day work = 1/12 + 1/15 + 1/20 = 12/60 = 1/5. Therefore, (A + B + C)'s 1-day work = 1/10. Working together, they finish in 10 days.
This question belongs to:
Maths
Time and Work
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