Question

If you invest 300 dollars in an account at 7.5 percent interest per year simple interest how much will you bave in the account at the beggining of the 11th year

Answer 1

keeping in mind that the interest is accumulated as time passes by, so "at the beginning of the 11th year", we're in the 11th year, just beginning, however, only 10 years have passed by, so after 10 years then.

$\bf ~~~~~~ \textit{Simple Interest Earned Amount} \\\\ A=P(1+rt)\qquad \begin{cases} A=\textit{accumulated amount}\\ P=\textit{original amount deposited}\dotfill & \ 300\\ r=rate\to 7.5\%\to \frac{7.5}{100}\dotfill &0.075\\ t=years\dotfill &10 \end{cases} \\\\\\ A=300[1+(0.075)(10)]\implies A=300(1.75)\implies A=525$