A can do a piece of work in 30 days, B in 50 days and C in 40 days. If A is assisted by B on one day and by C on the next day alternately, the work will be completed in:
Show answer & explanation
Correct answer: B
Explanation
The correct answer is option 2 i.e. 17(32/35) days
A can do a piece of work in 30 days, B in 50 days, and C in 40 days.
Total amount of work = L.C.M of (30, 50, 40) = 600
Work done by A in a day = 600/30 = 20 units
Work done by B in a day = 600/50 = 12 units
Work done by C in a day = 600/40 = 15 units
(A + B)'s work in a day = 20 + 12 = 32
(A + C)'s work in a day = 20 + 15 = 35
Work done in first two days = 32 + 35 = 67
Amount of work done in 16 days = 16(67)/2 = 536
Work done on 17th day = 32 units
Remaining work = 600 - 536 - 32 = 600 - 568 = 32 units
The remaining work will be done in = 32/35 days
Thus, the total work will be completed in = 17 (32/35) days