A and B can do a work in 5 days, B and C in 15 days and C and A in 25 days. In how many days will the work be completed, if all three of them work together?
Options:
(A) 26/18
(B) 42/15
(C) 48/63
(D) 12/36
(E) 150/23 Hmmm, my stream of consciousness:
One day work of A and B = 1/5
One day work of B and C = 1/15
One day work of C and A = 1/25
2(A + B + C) = 1/5+ 1/15 + 1/25
2(A + B + C) = 23/75
(A + B + C) = 23/150
Number of days required = 150/23 days. So, the answer is (E).