Answer:
Step-by-step explanation:
For sales of 's', Alan's earnings will be ...
 320 +0.05s
He wants that to be at least 600, so the inequality is ...
 320 +0.05s ≥ 600
__
Its solution is found by subtracting 320 and dividing by 0.05.
 0.05s ≥ 280
 s ≥ 5600
Alan's weekly sales must be at least $5600 for his earnings to cover his expenses.