[tex]~~~~~~ \textit{Compound Interest Earned Amount} \\\\ A=P\left(1+\frac{r}{n}\right)^{nt} \quad \begin{cases} A=\textit{accumulated amount}\dotfill &\$68000\\ P=\textit{original amount deposited}\\ r=rate\to 3.575\%\to \frac{3.575}{100}\dotfill &0.03575\\ n= \begin{array}{llll} \textit{times it compounds per year}\\ \textit{quarterly, thus four} \end{array}\dotfill &4\\ t=years\dotfill &30 \end{cases}[/tex]
[tex]68000=P\left(1+\frac{0.03575}{4}\right)^{4\cdot 30}\implies 68000=P(1.0089375)^{120} \\\\\\ \cfrac{68000}{1.0089375^{120}}=P\implies 23377\approx P[/tex]