A, B, and C can do a piece of work in 20 days, 30 days, and 60 days respectively. If A works daily and on every third day B and C also work with A, then in how many days, will the work be completed?
Show answer & explanation
Correct answer: D
Explanation
The correct answer is Option 4 i.e. 15.
A, B, and C can do a piece of work in 20 days, 30 days, and 60 days respectively
Total work (L.C.M of 20, 30, and 60) = 60
The efficiency of A = 60/20 = 3 units
The efficiency of B = 60/30 = 2 units
The efficiency of C = 60/60 = 1 units
A works daily and on every third day B and C also work with A
1st day work of A = 3 units
2nd day work of A = 3 units
3rd day work of A + B + C = 6 units
Total work in 3 days = 12 units (Multiply by 5)
Thus, 60 units of work will be completed in 3 × 5 = 15 days