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?
A.3
B.2✓ Correct
C.2.5
D.1.5
Explanation
A+B+C = 1/36. A+B = 5C gives 6C = 1/36, C = 1/216. B+C = A gives 2A = 1/36, A = 1/72. Then B = 1/36 − 1/72 − 1/216 = (6−3−1)/216 = 2/216 = 1/108. A+C = 1/72+1/216 = 4/216. (A+C)/B = (4/216)/(1/108) = 2.
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