Evaluate the integral by integrating with respect to $x,y,$ and $z.$

${\displaystyle \underset{0}{\overset{15}{}}}{\displaystyle \underset{0}{\overset{6}{}}}{\displaystyle \underset{x=\frac{y}{2}}{\overset{x=\frac{y}{2}+1}{}}}(\frac{2x-y}{2}+\frac{z}{5})dxdydz$