Pawan completes 40% of a task in 6 days. His efficiency

Solution

ATQ,
Pawan’ alone can do the complete work in (6/0.4) = 15 days
Efficiency of ‘Pawan’ = 2 × efficiency of ‘Qureshi’
As, we know efficiency is inversely proportional to time taken when work done is constant.
So, ‘Qureshi’ alone can complete the work = (15 × 2) = 30 days
Let the total work be 30 units {LCM of 15 and 30}
Efficiency of ‘Pawan’ = (30/15) = 2 units/day
Efficiency of ‘Qureshi’ = (30/30) = 1 unit/day
So, time taken by ‘Pawan’ and ‘Qureshi’ to complete the work together = (30/3) = 10 days