The rate of simple interest per annum reduces from 4 % to 3 3 4 % and for this, a person's annual income decreases by ₹ 60 . Determine the principle of that person.

The simple interest when R = 4 % , T = 1 year , P = P Simple Interest S 1 = P T R 100 = P × 1 × 4 100 = P 25 Total income I 1 = P + P 25 = 26 P 25 The simple interest when R = 3 3 4 % = 15 4 % , T = 1 year , P = P Simple Interest S 2 = P T R 100 = P × 1 × 15 4 100 = 15 P 400 = 3 P 80 Total income I 2 = P + 3 P 80 = 83 P 80 According to the question = I 1 - I 2 = ₹ 60 26 P 25 - 83 P 80 = 60 416 P 400 - 415 P 400 = 60 P 400 = 60 P = 400 × 60 = 24000 Hence, the required answer is ₹ 24000 .