A is 50% more efficient than B. C does half of the work done by A and B together in the same time. If C alone can do the work in 40 days, then A, B and C together can do the work in: MCQ with Answer and Explanation

A is 50% more efficient than B. C does half of the work done by A and B together in the same time. If C alone can do the work in 40 days, then A, B and C together can do the work in:
A. 13(1/3) days
B. 30 days
C. 20 days
D. 15 days
Answer: Option A
Solution (By JKSSB Mock Tests)
Let efficiency of B = 2, then efficiency of A = 3. Combined efficiency of A and B = 5. Efficiency of C = 5 / 2 = 2.5. Total work = Efficiency of C * Time taken by C = 2.5 * 40 = 100 units. Combined efficiency of A, B and C = 3 + 2 + 2.5 = 7.5 units/day. Time taken together = 100 / 7.5 = 1000 / 75 = 40 / 3 = 13(1/3) 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 30 days and B alone in 22 days. What percentage of the total daily work is contributed by A?
A. 42.31
B. 49.81
C. 44.81
D. 47.31

Correct Answer: Option A


Explanation:
A share = (1/30) / (1/30+1/22) ×100 = 42.31%.

This question belongs to: Maths Time and Work
Question #2
A can complete a work in 21 days and B in 25 days. If they work together, the work will be completed in:
A. 11.41
B. 16.41
C. 21.41
D. 26.41

Correct Answer: Option A


Explanation:
Combined rate = 1/21 + 1/25. Required time = 11.41 days.

This question belongs to: Maths Time and Work
Question #3
A can complete a work in 24 days and B can complete the same work in 24 days. If they work together, in how many days will the work be completed?
A. 16.0
B. 18.0
C. 12.0
D. 14.0

Correct Answer: Option C


Explanation:
Combined rate = 1/24 + 1/24. Time = 1 ÷ combined rate = 12.0 days.

This question belongs to: Maths Time and Work