Explanation:
Let's denote the number of hours Nathan works delivering pizzas as "x" and the number of hours he works babysitting as "y." We can set up the following system of inequalities:
Nathan's total earnings should be at least $40:
10x + 5y ≥ 40
Nathan's total working hours should be less than six hours a week:
x + y < 6
These two inequalities represent the given conditions that Nathan wants to make at least $40 and work for less than six hours a week.