Question

you invested $1000 and at the end of one year you had $1090. What was the annual intetest on the investment? Presume simple interest and not compounded.

Answer 1

The interest rate will be found as follows:
I=(PRT)
I=1090-1000=$90
thus plugging in the value we get:
90=(1000*R*1)
90=1000R
thus
R=90/1000
R=0.09~9%