Jiao works at least 36 h/wk. She earns $15/h as a science tutor and $25/h as a teacher. The number of hours Jiao works as a teacher, y, is at least twice the number of hours she works as a tutor, x. This set of inequalities represents the constraints in this situation. x+y≥36y≥2xx≥0 The objective function is I = 15x + 25y, where I represents Jiao's income for a week. What is the minimum amount of money she can earn in a week?