A, B, and C can complete a piece of work in 12, 15, and 20 days respectively. In how many days will they finish it together? MCQ with Answer and Explanation

A, B, and C can complete a piece of work in 12, 15, and 20 days respectively. In how many days will they finish it together?
A. 8 days
B. 5 days
C. 4 days
D. 6 days
Answer: Option B
Solution (By JKSSB Mock Tests)
Total work = LCM of 12, 15, and 20 = 60 units. Efficiency of A = 5, B = 4, C = 3. Total efficiency = 5 + 4 + 3 = 12 units/day. Days required = 60 / 12 = 5 days.

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Practice More Time and Work Questions

Question #1
A can complete a work in 15 days and B in 30 days. After working together for 5 days, what percentage of work remains?
A. 52.5
B. 57.5
C. 50.0
D. 55.0

Correct Answer: Option C


Explanation:
Remaining work = (1 - 5*(1/15+1/30))×100 = 50.0%.

This question belongs to: Maths Time and Work
Question #2
A can complete a work in 11 days and B can complete the same work in 21 days. If they work together, in how many days will the work be completed?
A. 13.22
B. 11.22
C. 7.22
D. 9.22

Correct Answer: Option C


Explanation:
Combined rate = 1/11 + 1/21. Time = 1 ÷ combined rate = 7.22 days.

This question belongs to: Maths Time and Work
Question #3
4 men and 6 women can complete a work in 8 days, while 3 men and 7 women can complete it in 10 days. In how many days will 10 women complete the work?
A. 40 days
B. 50 days
C. 45 days
D. 35 days

Correct Answer: Option A


Explanation:
Total work = 8 * (4M + 6W) = 10 * (3M + 7W) => 32M + 48W = 30M + 70W => 2M = 22W => 1M = 11W. Total work = 8 * (4*11W + 6W) = 8 * 50W = 400W. Time taken by 10 women = 400W / 10W = 40 days.

This question belongs to: Maths Time and Work