Solutions
Assume that total work = 80 units. (We assumed this number to keep the calculation easy, as time taken by Ram to do 100% comes out to 80 days)
Ram completes 40% of a task in 32 days.
∴ Ram completes 40% of 80 = 32 units of the task in 32 days.
∴ His efficiency = (32 ÷ 32) = 1 unit/day.
Mayank is 80% as efficient as Ram is.
∴ Mayank’s efficiency = 0.8 unit/day.
Virat is 50% as efficient as Mayank is.
∴ Virat’s efficiency = 0.4 unit/day.
Total efficiency when they work together = (1 + 0.8 + 0.4) = 2.2 units/day
Remaining work after 32 days = (80 – 32) = 48 units.
Time required to complete this work when they work together = (48 ÷ 2.2) ≈ 21.8 days.