The rate of interest for the first 2 years is 5% for the next 3 years is 8% and beyond this. It is 10% per annum. If the simple interest for 8 years is Rs . 1280. What is the principal?
Correct Answer: Rs. 2000
Explanation:
r1 = 5%,
r2 = 8%,
r3 = 10%, t1 = 2 years
t2 = 3 years,
t3 = 8 - (2 + 3) = 3 years
∵ Principal = (Interest x 100) / [(r1 x t1) + (r2 x t2) + (r3 x t3 )] = (1280 x 100) / (5 x 2 + 8 x 3 + 10 x 3)
= 128000/(10 + 24 + 30)
= 128000/64
=Rs. 2000
