Question

If p is rs 12000 N is 8 years I is rs 8640 then r ?

Answer 1

which interest you want simple or compound

Answer 2

$i = prn \frac{1}{100 } \\ \: \: \: 8640= 12000 \times 8 \times r \frac{1}{100} \\ 8640 = 960r \\ r = 9$