A, B and C can do a piece of work in 20, 30 and 60 days respectively. In how many days can A do the work if he is assisted by B and C on every third day?\nOptions:\n(A) 12 days\n(B) 15 days\n(C) 18 days\n(D) 20 days\n(E) 22 days Hmmm, my stream of consciousness:
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A’s two day’s work = 2/20 = 1/10\n(A + B + C)’s one day’s work = 1/20 + 1/30 + 1/60 = 6/60 = 1/10\nWork done in 3 days = (1/10 + 1/10) = 1/5\nNow, 1/5 work is done in 3 days\nTherefore, Whole work will be done in (3 x 5) = 15 days. So, the answer is (C).
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