Answer: We know that:
x + y = 12 (because he can work at most 12 hours in total)
7x + 10y ≥ 90 (because he must earn no less than $90)
We can graph these inequalities on the coordinate plane.
The equation x + y = 12 represents a line with a slope of -1 and y-intercept of 12. This is the line that separates the region where he works more hours babysitting and the region where he works more hours clearing tables.
The inequality 7x + 10y ≥ 90 represents the region where he earns more than $90.
You can find the solution by finding the intersection of the line and the shaded region. The solution will be a point that lies on both the line and the shaded region.
One possible solution would be for Mason to work 8 hours babysitting and 4 hours clearing tables, earning him $56 from babysitting and $40 from clearing tables, for a total of $96.
Explanation: