[tex] \bf \stackrel{\textit{current age}}{a}~~
\begin{cases}
\stackrel{\textit{5 years ago}}{a-5}\\
\stackrel{\textit{8 years from now}}{a+8}
\end{cases}\\\\
-------------------------------\\\\
\stackrel{\textit{5 years ago}}{a-5}~~=~~\cfrac{\stackrel{\stackrel{half}{\textit{8 years from now}}}{a+8}}{2}
\\\\\\
\stackrel{\textit{multiplying both sides by }\stackrel{LCD}{2}}{2a-10=a+8}
\implies a=18 [/tex]
