A can do a certain work in the same time in which B and C together can do it. If A and B together could do it in 10 days and C alone in 50 days, then B alone could do it in: MCQ with Answer and Explanation

A can do a certain work in the same time in which B and C together can do it. If A and B together could do it in 10 days and C alone in 50 days, then B alone could do it in:
A. 35 days
B. 25 days
C. 20 days
D. 30 days
Answer: Option B
Solution (By JKSSB Mock Tests)
Total work = LCM(10, 50) = 50 units. Efficiency of (A + B) = 5, efficiency of C = 1. Total efficiency of (A + B + C) = 5 + 1 = 6. Given A = B + C. So, (B + C) + B + C = 6 => 2(B + C) = 6 => B + C = 3. Since C = 1, B = 2. Time taken by B alone = 50 / 2 = 25 days.

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Practice More Time and Work Questions

Question #1
A can complete a work in 11 days and B in 30 days. If they work together, the work will be completed in:
A. 8.05
B. 13.05
C. 18.05
D. 23.05

Correct Answer: Option A


Explanation:
Combined rate = 1/11 + 1/30. Required time = 8.05 days.

This question belongs to: Maths Time and Work
Question #2
A can do a work in 4 days, B in 5 days and C in 10 days. Find the time taken by A, B and C together to do the work.
A. 2 days
B. 1(9/11) days
C. 2(1/11) days
D. 1(7/11) days

Correct Answer: Option B


Explanation:
Total work = LCM(4, 5, 10) = 20 units. Efficiency of A = 5, B = 4, C = 2. Combined efficiency = 5 + 4 + 2 = 11 units/day. Time taken together = 20 / 11 = 1(9/11) days.

This question belongs to: Maths Time and Work
Question #3
A can complete a work in 8 days and B in 21 days. If they work together, the work will be completed in:
A. 20.79
B. 5.79
C. 15.79
D. 10.79

Correct Answer: Option B


Explanation:
Combined rate = 1/8 + 1/21. Required time = 5.79 days.

This question belongs to: Maths Time and Work