Question

5. Joyce took out a small loan for $1.200. The interest on the loan was 10.5%, bu

she paid it back in just 18 months. How much did she pay back in interest?

Answer 1

keeping in mind that a year has 12 months, so that means that 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 & \$1200\\ r=rate\to 10.5\%\to (10.5)/(100)\dotfill &0.105\\ t=years\to (18)/(12)\dotfill &(3)/(2) \end{cases} \\\\\\ I = (1200)(0.105)((3)/(2))\implies 189`