[tex]\bf \begin{array}{cll}
term&value\\
\text{\textemdash\textemdash\textemdash}&\text{\textemdash\textemdash\textemdash}\\
a_1&15\\
a_2&15\left( \frac{1}{3} \right)\\\\
a_3&15\left( \frac{1}{3} \right)\left( \frac{1}{3} \right)\\\\
a_4&15\left( \frac{1}{3} \right)\left( \frac{1}{3} \right)\left( \frac{1}{3} \right)
\end{array}\qquad \implies 15\left( \frac{1}{3} \right)^3\implies 15\cdot \cfrac{1^3}{3^3}
\\\\\\
\cfrac{15}{27}\implies \stackrel{simplified}{\cfrac{5}{9}}[/tex]
