Question

Find the simple interest.
Principal $300
The interest Rate 15%
Time 18 months

Answer 1

keeping in mind that a year has 12 months, thus 18 months is really 18/12 of a year.

`~~~~~~ \textit{Simple Interest Earned} \\\\ I = Prt\qquad \begin{cases} I=\textit{interest earned}\\ P=\textit{original amount deposited}\dotfill & \$300\\ r=rate\to 15\%\to (15)/(100)\dotfill &0.15\\ t=years\to (18)/(12)\dotfill &(3)/(2) \end{cases} \\\\\\ I = (300)(0.15)((3)/(2))\implies I=67.5`