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:

A can complete the work in 30 days.

B can complete the work in 50 days.

C can complete the work in 40 days.

A is assisted alternately by B on one day and by C on the next day.

Formula Used:​

Total work = Efficiency $$\times$$ Time​
Solution:

Total work = LCM of (30, 50, 40) = 600 unit
Now, efficiency of A = 20 unit, B = 12 unit, and C = 15 unit
Work done on 1st day (A + B) = 20 + 12 = 32 unit
Work done on 2nd day (A + C) = 20 + 15 = 35 unit
So, in every 2 days they done (35 + 32) = 67 unit work
Now, in 17 days they done (67 × 8) + 32 = 568 unit
Remaining (600 - 568) = 32 unit of work done by (A + C) in 32/35 days
So, the work will be complete in 17 + 32/35 = 17$$\frac{32}{35}$$ days