Question

If the simple interest on $4000 for 9 years is $1800, then what is the interest rate.

Answer 1

5%

Explanation:

4000 × 9 × r = 1800

r = 1800/36000

r = 0.05 × 100

5%

Answer 2

9% or 0.09

Explanation:

so 1800/4000 is .45 then we do .45/5 which is 0.09 and if u wanna double check do 4000 x 0.09 then that gives us 360 then we do 360 x 5 for 5 years that you've been investing which leaves us with 1800 which is the interest you got.