Three persons A, B and C together can do a piece of work in 36 days. A and B together can do five times as much work as C alone; B and C together can do as much work as A alone. If A and C together can do n times as much work as B alone, then what is the value of n?

  1. A. 1.5
  2. B. 2
  3. C. 2.5
  4. D. 3

Correct Answer: B. 2

Explanation

Let efficiencies be A, B, C. Given A+B = 5C, so A+B+C = 6C. Also B+C = A, so A+B+C = 2A. Thus 2A = 6C \implies A = 3C. Since B+C = A = 3C, we get B = 2C. We need A+C = nB \implies 3C+C = n(2C) \implies 4C = 2nC \implies n = 2.

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