Question

What interest is paid for three months
on $ 860 at 2 1/4% annual interest paid quarterly

Answer 1

we know that a year is 12 months, so 3 months is really 3/12 of a year. Also let's recall that 2¼ is just 2.25, so

`~~~~~~ \textit{Simple Interest Earned} \\\\ I = Prt\qquad \begin{cases} I=\textit{interest earned}\\ P=\textit{original amount deposited}\dotfill & \$860\\ r=rate\to 2.25\%\to (2.25)/(100)\dotfill &0.0225\\ t=years\to (3)/(12)\dotfill &(1)/(4) \end{cases} \\\\\\ I = (860)(0.0225)((1)/(4)) \implies I \approx 4.84`