[tex]\bf \qquad \qquad \textit{Future Value of an ordinary annuity}
\\\\
A=pymnt\left[ \cfrac{\left( 1+\frac{r}{n} \right)^{nt}-1}{\frac{r}{n}} \right][/tex]
[tex]\bf \begin{cases}
A=
\begin{array}{llll}
\textit{accumulated amount}\\
\end{array}\to &
\begin{array}{llll}
900
\end{array}\\
pymnt=\textit{periodic payments}\\
r=rate\to 8.4\%\to \frac{8.4}{100}\to &0.084\\
n=
\begin{array}{llll}
\textit{times it compounds per year}\\
\textit{monthly payments, thus}
\end{array}\to &12\\
t=years\to \frac{6}{12}\to &\frac{1}{2}
\end{cases}
\\\\\\
900=pymnt\left[ \cfrac{\left( 1+\frac{0.084}{12} \right)^{12\cdot \frac{1}{2}}-1}{\frac{0.084}{12}} \right][/tex]
solve for "pymnt"
