Question

The SUM of £1640 is invested in a banck the rate of intrest is 4. 5% annum. Claculate the simple intrest gained in 9 months

Answer 1

keeping in mind that a year has 12 months, thus 9 months are really 9/12 of a year, so

`~~~~~~ \textit{Simple Interest Earned} \\\\ I = Prt\qquad \begin{cases} I=\textit{interest earned}\\ P=\textit{original amount deposited}\dotfill & \pounds 1640\\ r=rate\to 4.5\%\to (4.5)/(100)\dotfill &0.045\\ t=years\to (9)/(12)\dotfill &(3)/(4) \end{cases} \\\\\\ I = (1640)(0.045)((3)/(4))\implies I=55.35`