smc

Suppose $x$ is the price of an adult ticket. The price of a child ticket would be $\frac{x}{2}$. \begin{eqnarray} 5x + 4(x/2) = 7x &=& 24.50\\ x &=& 3.50\\ \end{eqnarray} Plug in for 8 adult tickets and 6 child tickets. \begin{eqnarray} 8x + 6(x/2) &=& 8(3.50) + 3(3.50)\\ &=&\boxed{\textdollar38.50}\\ \end{eqnarray}