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? MCQ with Answer and Explanation

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?
A. 35 days
B. 25 days
C. 30 days
D. 24 days
Answer: Option C
Solution (By JKSSB Mock Tests)
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.

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Practice More Time and Work Questions

Question #1
A and B work together. A alone can complete the work in 18 days and B alone in 36 days. What percentage of the total daily work is contributed by A?
A. 69.17
B. 71.67
C. 66.67
D. 74.17

Correct Answer: Option C


Explanation:
A share = (1/18) / (1/18+1/36) ×100 = 66.67%.

This question belongs to: Maths Time and Work
Question #2
15 men can complete a work in 22 days. If 20 men work at the same rate, the work will be completed in:
A. 31.5
B. 26.5
C. 16.5
D. 21.5

Correct Answer: Option C


Explanation:
Total work = 330 man-days. Time = 330/20 = 16.5 days.

This question belongs to: Maths Time and Work
Question #3
A can complete a work in 17 days and B in 44 days. If both work together, in how many days will the work be completed?
A. 19.76
B. 12.26
C. 17.26
D. 14.76

Correct Answer: Option B


Explanation:
Combined rate = 1/17 + 1/44. Time = 12.26 days.

This question belongs to: Maths Time and Work