Give stream of consciousness and then the final answer. Two persons A and B can complete a piece of work in 30 days and 45 days respectively. If they work together, what part of the work will be completed in 7 days?
Options:
(A) 2/5
(B) 7/18
(C) 1/4
(D) 1/9
(E) 2/6
user
A's one day's work = 1/30
B's one day's work = 1/45
(A + B)'s one day's work = 1/30 + 1/45 = 1/18
The part of the work completed in 7 days = 7 (1/18) = 7/18.
The final answer: (B).
assistant