S can complete a task in 50 days, T can complete it in 40 days and M can complete it in 30 days. S can work on all days of the week; T can work only on Monday, Wednesday, and Friday while M can work only on Saturday and Sunday. The work is started on Monday. In how many weeks it will be completed?
Show answer & explanation
Correct answer: C
Explanation
The correct answer is Option 3 i.e. Between 3 to 4 weeks.
S can complete a task in 50 days, T can complete it in 40 days and M can complete it in 30 days
L.C.M(50, 40 and, 30) = 600
The efficiency of S = 600/50 = 12 units
The efficiency of T = 600/40 = 15 units
The efficiency of M = 600/30 = 20 units
Work done in one week = 12 × 7 + 15 × 3 + 20 × 2 = 84 + 45 + 40 = 169 units
Total weeks to complete the whole work = 600/169 = 3.55 weeks or between 3 to 4 weeks