Sketch the Feasible Region, and Use Linear Programming to Find $\mathrm{z}$

Sketch the feasible region, and use linear programming to find the maximum value of $\mathrm{z}$ on the feasible region.
-A yoga studio will offer a workshop provided that at least 20 people sign up. Beginning students require more attention than experienced students and the number of assistants in the class will be limited to three. For this reason, the teacher would like the number of experienced students to be at least twice the number of beginners. Set up and graph a system of inequalities for the situation, letting $\mathrm{x}$ represent the number of beginning students and $\mathrm{y}$ the number of experienced students.