Correct Answer - Option 4 : 20 months
Given:
Initial investments' ratio of A and B = 4: 5
Ratio of their annual profits = 3: 5
Calculation
Let us assume that
A invests 4x amount for 10 months and
B invests 5x amount for y months
According to the question,
(4x × 10)/(5x × y) = 2/5
20x × 10 = 10xy
Y = 20 months
Hence, B invested for 20 months