The ratio of difference between CI and SI for 2 years to the difference of CI and SI for 3 years is 8 : 25. Find rate of interest.

12.5%

Here, In the above figure,

(A*) = Difference b/w CI. and SI. for 2 years.

(A* + A + A + B) = (3A + B) = Difference b/w CI. and SI. for 3 years.

ATQ,

(A*) : (3A + B) = 8 : 25

A = 8,

3A + B = 25

24 + B = 25

B = 1

B is x% interest on A, therefore,

Rate of Interest = \(\frac{1}{8}\) × 100% = 12.5%