Tahsan took a loan at simple interest rate of 6 p.c.p.a. in the first year and it increased by 1.5 p.c.p.a. every year. If he pays Tk. 8190 as interest at the end of 3 years, what was his loan amount?

Question: Tahsan took a loan at simple interest rate of 6 p.c.p.a. in the first year and it increased by 1.5 p.c.p.a. every year. If he pays Tk. 8190 as interest at the end of 3 years, what was his loan amount?

Solution:
Let the loan amount be Tk. x

ATQ,
6% of x + 7.5% of x + 9% of x = 8190
⇒ (6x/100) + (7.5x/100) + (9x/100) = 8190
⇒ 22.5x = 819000
∴ x = 36400