Writing linear inequalities

Feb 2013
42
0
New York City
You can work at most 20 hours next week. You need to earn at least $92 to cover your weekly expenses. Your dog-walking job pays $7.50 per hour and your job as a car wash attendant pays $6 per hour. Write a system of linear inequalities to model the situation.
 
Dec 2013
2,002
757
Colombia
Let $d$ be the number of hours spent dog-walking and $c$ be the number of hours spent attending to the car-wash.

Then $b+c \le 20$ by the first sentence and $7.5 b + 6c \ge 92$.