A can complete a work in 13 days and B in 42 days. If both work together, in how many days will the work be completed? MCQ with Answer and Explanation
Question
Report Error
Discuss this Question (0)
Practice More Time and Work Questions
Question #1
Report Error
A can complete a work in 13 days and B in 17 days. If they work together, the work will be completed in:
Correct Answer: Option C
Explanation:
Combined rate = 1/13 + 1/17. Required time = 7.37 days.
Combined rate = 1/13 + 1/17. Required time = 7.37 days.
This question belongs to:
Maths
Time and Work
Question #2
Report Error
A can build a wall in 15 days, and B can destroy it in 20 days. If they work on alternate days starting with A, in how many days will the wall be built?
Correct Answer: Option A
Explanation:
Total work = LCM(15, 20) = 60 units. Efficiency of A = +4, B = -3. In 2 days (A then B), net work done = 4 - 3 = 1 unit. We need to reach 60 - 4 = 56 units first. 56 units will be done in 56 * 2 = 112 days. On the 113th day, A works and completes 4 units, making the total work 56 + 4 = 60 units. So, the wall is completed in 113 days.
Total work = LCM(15, 20) = 60 units. Efficiency of A = +4, B = -3. In 2 days (A then B), net work done = 4 - 3 = 1 unit. We need to reach 60 - 4 = 56 units first. 56 units will be done in 56 * 2 = 112 days. On the 113th day, A works and completes 4 units, making the total work 56 + 4 = 60 units. So, the wall is completed in 113 days.
This question belongs to:
Maths
Time and Work
Question #3
Report Error
A can complete a work in 12 days and B in 40 days. If both work together, in how many days will the work be completed?
Correct Answer: Option C
Explanation:
Combined rate = 1/12 + 1/40. Time = 9.23 days.
Combined rate = 1/12 + 1/40. Time = 9.23 days.
This question belongs to:
Maths
Time and Work
No comments yet. Be the first to start the discussion!