A can do a piece of work in 20 days and B in 30 days. They work together for 7 days and then both leave. Then C alone finishes the remaining work in 10 days. In how many days can C alone finish the full work? MCQ with Answer and Explanation
Question
Report Error
Discuss this Question (0)
Practice More Time and Work Questions
Question #1
Report Error
12 men can complete a work in 28 days. If 16 men work at the same rate, in how many days will the work be completed?
Correct Answer: Option B
Explanation:
Total work = 12 × 28 = 336 man-days. Required days = 336/16 = 21.0 days.
Total work = 12 × 28 = 336 man-days. Required days = 336/16 = 21.0 days.
This question belongs to:
Maths
Time and Work
Question #2
Report Error
A, B and C can do a piece of work in 10, 12 and 15 days respectively. They began the work together but A left after 2 days and B left 3 days before the completion of the work. How long did the work last?
Correct Answer: Option A
Explanation:
Total work = LCM(10, 12, 15) = 60 units. Efficiency of A = 6, B = 5, C = 4. Let the total time be x days. A worked for 2 days. B worked for (x - 3) days. C worked for x days. Total work = 2*6 + (x - 3)*5 + x*4 = 60 => 12 + 5x - 15 + 4x = 60 => 9x - 3 = 60 => 9x = 63 => x = 7 days.
Total work = LCM(10, 12, 15) = 60 units. Efficiency of A = 6, B = 5, C = 4. Let the total time be x days. A worked for 2 days. B worked for (x - 3) days. C worked for x days. Total work = 2*6 + (x - 3)*5 + x*4 = 60 => 12 + 5x - 15 + 4x = 60 => 9x - 3 = 60 => 9x = 63 => x = 7 days.
This question belongs to:
Maths
Time and Work
Question #3
Report Error
A can complete a work in 20 days and B in 30 days. They start together but A leaves after 4 days. In how many total days will the work be completed?
Correct Answer: Option A
Explanation:
Total work = LCM(20, 30) = 60 units. Efficiency of A = 3, B = 2. In 4 days, work completed = 4 * (3 + 2) = 20 units. Remaining work = 60 - 20 = 40 units. Time taken by B to finish remaining work = 40 / 2 = 20 days. Total days = 4 + 20 = 24 days.
Total work = LCM(20, 30) = 60 units. Efficiency of A = 3, B = 2. In 4 days, work completed = 4 * (3 + 2) = 20 units. Remaining work = 60 - 20 = 40 units. Time taken by B to finish remaining work = 40 / 2 = 20 days. Total days = 4 + 20 = 24 days.
This question belongs to:
Maths
Time and Work
No comments yet. Be the first to start the discussion!