Answer
They should deposit $7710.99
Explanation
Using compound interest formula,
[tex]A=P(1+\frac{r}{n})^{nt}[/tex]Where:
A = Amount = $20,000
P = Principal = ?
r = Interesr rate = 10% = 0.1
n = 1
t = 10
[tex]\begin{gathered} \Rightarrow20000=P(1+0.1)^{1\times10} \\ 20000=P(1.1)^{10} \\ 20000=P(2.5937) \\ \text{Divide both sides by 2.5937} \\ \frac{P\mleft(2.5937\mright)}{2.5937}=\frac{20000}{2.5937} \\ P=7710.9920 \\ \text{To the nearest cent, the answer is} \\ P=7710.99 \end{gathered}[/tex]