A sketch artist sells on-demand portraits and name doodles at the state fair. The artist has a personal maximum of 40 creations per day. With his current paper supply, the artist is equipped
to create up to 30 portraits and up to 20 doodles. If the artist's profit is $10 on each portrait and
$20 on each name doodle, how many of each item should he aim to sell to maximize his profit? Write a system of inequalities