A can do a piece of work in 25 days and B can finish it in 20 days. They work together for 5 days and then A leaves. In how many days will B finish the remaining work? MCQ with Answer and Explanation
Question
Report Error
Discuss this Question (0)
Practice More Time and Work Questions
Question #1
Report Error
A can do a piece of work in 80 days. He works at it for 10 days and then B alone finishes the remaining work in 42 days. In how many days will A and B together complete the work?
Correct Answer: Option D
Explanation:
A's 10-day work = 10/80 = 1/8. Remaining work = 7/8. B completes 7/8 work in 42 days, so B completes full work in 42 * (8/7) = 48 days. Combined 1-day work = 1/80 + 1/48 = (3 + 5)/240 = 8/240 = 1/30. They finish together in 30 days.
A's 10-day work = 10/80 = 1/8. Remaining work = 7/8. B completes 7/8 work in 42 days, so B completes full work in 42 * (8/7) = 48 days. Combined 1-day work = 1/80 + 1/48 = (3 + 5)/240 = 8/240 = 1/30. They finish together in 30 days.
This question belongs to:
Maths
Time and Work
Question #2
Report Error
A can complete a work in 20 days and B in 36 days. If both work together, in how many days will the work be completed?
Correct Answer: Option D
Explanation:
Combined rate = 1/20 + 1/36. Time = 12.86 days.
Combined rate = 1/20 + 1/36. Time = 12.86 days.
This question belongs to:
Maths
Time and Work
Question #3
Report Error
A and B can complete a work in 15 days and 10 days respectively. They started the work together but B left after 2 days. In how many days will A complete the remaining work?
Correct Answer: Option B
Explanation:
Total work = LCM(15, 10) = 30 units. Efficiency of A = 2, B = 3. Combined efficiency = 5 units/day. In 2 days, work completed = 2 * 5 = 10 units. Remaining work = 30 - 10 = 20 units. Time taken by A to complete remaining work = 20 / 2 = 10 days.
Total work = LCM(15, 10) = 30 units. Efficiency of A = 2, B = 3. Combined efficiency = 5 units/day. In 2 days, work completed = 2 * 5 = 10 units. Remaining work = 30 - 10 = 20 units. Time taken by A to complete remaining work = 20 / 2 = 10 days.
This question belongs to:
Maths
Time and Work
No comments yet. Be the first to start the discussion!