Chapter A.7, Problem 51E

Interest rate. If $P$ dollars are invested at $100r$ percent compounded annually, at the end of $2$ years it will grow to $A=P{\left(1+r\right)}^2$. At what interest rate will $\text{\$}484$ grow to $\text{\$}625$ in $2$ years? (Note: If $A=625$ and $P=484$, find $r$.)