Linear Programming

The maximum value of $\mathrm{z}=3 \mathrm{x}+4 \mathrm{y}$, subject to the constraints $\mathrm{x}+\mathrm{y} \leq 40, \mathrm{x}+2 \mathrm{y} \leq 60$ and $\mathrm{x}, \mathrm{y} \geq 0$ is