A and B can do a piece of work in 12 days, B and C in 15 days, and C and A in 20 days. If A, B and C work together, in how many days will they complete the work? MCQ with Answer and Explanation
A and B can do a piece of work in 12 days, B and C in 15 days, and C and A in 20 days. If A, B and C work together, in how many days will they complete the work?
A. 10 days
B. 12 days
C. 8 days
D. 5 days
Answer: Option A
Solution (By JKSSB Mock Tests)
Total work = LCM(12, 15, 20) = 60 units. Efficiency of (A+B) = 5, (B+C) = 4, (C+A) = 3. Sum of efficiencies = 2 * (A+B+C) = 12 => Efficiency of (A+B+C) = 6 units/day. Time taken together = 60 / 6 = 10 days.
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