Delhi Police Constable Exam Model Paper 5

Given,
Efficiency A is more than B by = 25%
Formula :
Total work = Efficiency × Time
Calculation :
Let efficiency of B be 4 units/day
Efficiency of A = 4 × (5/4) = 5 units/day
Total work = 5 × 20 = 100 unit
∴ Time taken by B to complete the whole work = 100/4 = 25 days