Set up the linear programming problem.
Charlene baby-sits for $4 per hour. She also works as a tutor for $7 per hour. Because of school, her parents only allow her to work 13 hours per week. How many hours can Charlene tutor and baby-sit and still make at least $50 per week?
(a) Let x = hours spent baby-sitting and let y = hours spent tutoring. Write a system of inequalities for this situation.
(b) Graph the solution set.