Let's use the compound interest formula:
[tex]\begin{gathered} A=P(1+\frac{r}{n})^{nt} \\ \text{Where:} \\ A=\text{Amount}=100000 \\ P=\text{Initial investment}=10000 \\ r=\text{ Interest rate} \\ n=\text{Number of times interest is compounded per unit t}=1 \\ t=\text{time}=4 \end{gathered}[/tex][tex]\begin{gathered} 100000=10000(1+r)^{1\cdot1} \\ 10=(1+r) \\ 10=1+r \\ r=9 \end{gathered}[/tex]