Explain simply why (D) is the correct answer to: A and B can do a work in 6 days, B and C in 2 days and C and A in 8 days. In how many days will the work be completed, if all three of them work together?
Options:
(A) 12/24
(B) 48/63
(C) 45/56
(D) 48/19
(E) 28/12. Explanation:
One day work of A and B = 1/6
One day work of B and C = 1/2
One day work of C and A = 1/8
2(A + B + C) = 1/6 + 1/2 + 1/8
2(A + B + C) = 19/24
(A + B + C) = 19/48
Number of days required = 48/19 days.