15. Richie and Justin are doing house renovations for Kirk. Kirk has promised them at least 20 total hours of work per week, but can pay them no more than $1,200 per week of total wages, Richie makes $25 per hour
and Justin makes $45 per hour.
Letting x be the number of hours Richie works and y be the number of hours Justin works, write a system of
inequalities that models this situation.