now, we don't have a compounding period above, so we're assuming the amount is compounding annually.
[tex]~~~~~~ \textit{Compound Interest Earned Amount} \\\\ A=P\left(1+\frac{r}{n}\right)^{nt} \quad \begin{cases} A=\textit{accumulated amount}\dotfill &\pounds 8112\\ P=\textit{original amount deposited}\\ r=rate\to 30\%\to \frac{30}{100}\dotfill &0.30\\ n= \begin{array}{llll} \textit{times it compounds per year}\\ \textit{annually, thus once} \end{array}\dotfill &1\\ t=years\dotfill &2 \end{cases}[/tex]
[tex]8112=P\left(1+\frac{0.30}{1}\right)^{1\cdot 2}\implies 8112=P(1.3)^2\implies \cfrac{8112}{1.3^2}=P\implies 4800=P[/tex]
