karim deposited a sum $ 9000 in a bank after 2 years he withdrew $ 4000 and the end of 5 years he received $ 8300. find the rate of interest on the sum he recieved

Answer 1

at simple interest:
let the rate be r
at the end of 2 years : 9000 + 9000(2)(r)
he withdrew 4000
amount left = 5000 + 9000(2r) = 5000 + 18000r
Three more years :
5000 + 18000r + [5000 + 18000r](3r)
= 5000 + 18000r + 15000r + 54000r^2
= 8300
.....
r =