System of inequality

Question

Jacob is working two summer jobs, making $10 per hour washing cars and making $8 per hour landscaping. In a given week, he can work no more than 19 total hours and must earn at least $170. If Jacob worked 4 hours landscaping, determine the minimum number of whole hours washing cars that he must work to meet his requirements.

Answer 1

4(8) = 32

170 - 32 = 138

10c ≥ 138

c ≥ 13.8

14 hours