Question

You put $500 in your bank account.

With an interest rate of 5%, how long will it take the account to reach $600?

Use the formula I=prt.

Answer 1

when the account reaches 600, well, it had a Principal of $500, so to get there it'd need $100 more, so by the time the earned interest is 100, when is it?

`~~~~~~ \textit{Simple Interest Earned} \\\\ I = Prt\qquad \begin{cases} I=\textit{interest earned}\dotfill & \$ 100\\ P=\textit{original amount deposited}\dotfill & \$500\\ r=rate\to 5\%\to (5)/(100)\dotfill &0.05\\ t=years \end{cases} \\\\\\ 100 = (500)(0.05)(t) \implies \cfrac{100}{(500)(0.05)}=t\implies 4=t`