Answer :
[tex]\bf ~~~~~~ \textit{Simple Interest Earned Amount} \\\\ \begin{array}{llll} A=P+Prt\\\\ A=P(1+rt) \end{array} \qquad \begin{cases} A=\textit{accumulated amount}\dotfill&\$20000\\ P=\textit{original amount deposited}\\ r=rate\to 5\%\to \frac{5}{100}\dotfill &0.05\\ t=years\dotfill &10 \end{cases} \\\\\\ 20000=P(1+0.05\cdot 10)\implies 20000=P(1.5) \\\\\\ \cfrac{20000}{1.5}=P\implies 13333.\overline{3}=P\implies \stackrel{\textit{rounded up}}{13333=P}[/tex]