Question

Emma puts $10,000 in a simple interest account at a bank.

She will earn $1,800 in 4 years.

What is the annual interest rate for the account?

Answer 1

`~~~~~~ \textit{Simple Interest Earned} \\\\ I = Prt\qquad \begin{cases} I=\textit{interest earned}\dotfill & \$ 1800\\ P=\textit{original amount deposited}\dotfill & \$10000\\ r=rate\to r\%\to (r)/(100)\\ t=years\dotfill &4 \end{cases} \\\\\\ 1800 = (10000)((r)/(100))(4) \implies 1800=400r\implies \cfrac{1800}{400}=r\implies 4.5=r`