Question

Chris is a college student who can work a maximum of 40 hours per week. He needs to make at least $900 in order to cover his expenses. His tutoring job pays $25 per hour and he also makes $15 per hour refereeing soccer matches. Find the constraints for this situation and determine which point is a valid solution to the system, where x is the number of hours Chris spends tutoring and y is the number of hours he spends refereeing.

Answer 1

Equation 1: x + y = 40 ; therefore y = 40 - x
Equation 2: 25x + 15y = 900
Find x first:

25x + 15 (40 - x) = 900
25x + 600 - 15x = 900
10x = 900 - 600
x = 300÷10
x = 30 hours Chris needs to spend for tutoring job

y = 40 - 30
y = 10 hours Chris needs to spend for referencing job