Choice A is the correct answer. Calculate fixed costs first.

1. Fixed Cost: 3 days $\times$ $30/day = $90
2. Variable Cost: $0.15 per mile ($0.15m$)
3. Total Cost: $90 + 0.15m$
4. Inequality: $90 + 0.15m \leq 150$
5. Subtract 90: $0.15m \leq 60$
6. Divide by 0.15: $m \leq 400$

?�� Strategic Tip:$60 \div 0.15 = 6000 \div 15 = 400$.

Choice B is incorrect because it might result from dividing 120 by 0.15 (forgetting the 3-day cost). Choice C is incorrect because it might result from dividing 30 by 0.15. Choice D is incorrect because it might result from dividing 90 by 0.15.