A can complete a work in 30 days and B in 36 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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10 men can complete a piece of work in 15 days and 15 women can complete the same work in 12 days. If all the 10 men and 15 women work together, in how many days will the work be completed?
Correct Answer: Option C
Explanation:
1-day work of 10 men = 1/15. 1-day work of 15 women = 1/12. Combined 1-day work = 1/15 + 1/12 = (4 + 5) / 60 = 9 / 60 = 3 / 20. Total days required = 20 / 3 = 6(2/3) days.
1-day work of 10 men = 1/15. 1-day work of 15 women = 1/12. Combined 1-day work = 1/15 + 1/12 = (4 + 5) / 60 = 9 / 60 = 3 / 20. Total days required = 20 / 3 = 6(2/3) days.
This question belongs to:
Maths
Time and Work
Question #2
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A and B can complete a work together in 15 days. They work together for 3 days, then A leaves. If B alone completes the remaining work in 16 days, in how many days can A alone complete the whole work?
Correct Answer: Option B
Explanation:
Let the total work be 60 units. Combined efficiency of A and B = 60 / 15 = 4 units/day. In 3 days, they complete 3 * 4 = 12 units. Remaining work = 60 - 12 = 48 units. B completes 48 units in 16 days, so B's efficiency = 48 / 16 = 3 units/day. A's efficiency = 4 - 3 = 1 unit/day. Time taken by A alone = 60 / 1 = 60 days.
Let the total work be 60 units. Combined efficiency of A and B = 60 / 15 = 4 units/day. In 3 days, they complete 3 * 4 = 12 units. Remaining work = 60 - 12 = 48 units. B completes 48 units in 16 days, so B's efficiency = 48 / 16 = 3 units/day. A's efficiency = 4 - 3 = 1 unit/day. Time taken by A alone = 60 / 1 = 60 days.
This question belongs to:
Maths
Time and Work
Question #3
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A can complete a work in 23 days. What percentage of the work will be completed in 7 days?
Correct Answer: Option C
Explanation:
Completed percentage = (7/23)×100 = 30.43%.
Completed percentage = (7/23)×100 = 30.43%.
This question belongs to:
Maths
Time and Work
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