Question: Rs. 9000 is lent at the rate of 80 percent per annum on compound interest (compounded half yearly). what will be the compound interest of 12 months?

1. Rs.8700
2. Rs.9000
3. Rs.8640
4. Rs.8700

Answer: Rs. 8640

Solution:
interest= PXRXT/100
Compound interest be x
(9000(0.5)(0.8)+ 9000(1+0.5(0.8))(0.8)(0.5))/100
3600+5040
Rs 8640