Correct Answer - Option 2 : 50
Given:
A and B both working together can complete a work in 20 days
The efficiency of B and A are in ratio 2 : 3
Formula used:
Total Work = Efficiency × Time
Where Efficiency is work done per day.
Calculation:
Let the efficiency of B and A be 2x and 3x respectively.
⇒ Efficiency of (A + B) = 5x
⇒ Total work = 20 × 5x = 100x
According to the question,
⇒ B can complete the work in = 100x/2x = 50 days
∴ B alone can complete the work in 50 days.