I know this is an easy question but here goes;
Anjee bought a boat priced at $25000 and paid it off by making equal monthly repayments of $615 over 5 years. Find the annual interest rate that was charged
Solve for x
$\displaystyle 36900= 25000(1+x)^5$
Compound interest - Wikipedia, the free encyclopedia
Ok lets try this then
$\displaystyle \frac{11900}{5}= 2380$
so
$\displaystyle 27380=2380+25000$
Using the formula you used
$\displaystyle R=\frac{I}{PT}$
rearrange variables to solve for R
$\displaystyle 27380 = 25000(R)$