well, the returned interest is 2.77 flat, meaning Shawn is getting simple interest per day for those three days.
[tex]~~~~~~ \textit{Simple Interest Earned} \\\\ I = Prt\qquad \begin{cases} I=\textit{interest earned}\dotfill & \$\stackrel{3(2.77)}{8.31}\\ P=\textit{original amount deposited}\dotfill & \$1000\\ r=rate\to r\%\to \frac{r}{100}\\ t=years\dotfill &3 \end{cases} \\\\\\ 8.31 = (1000)(\frac{r}{100})(3)\implies 8.31=30r\implies \cfrac{8.31}{30}=r\implies \stackrel{\%}{0.277}=r[/tex]
