1. **State the problem:** Fran's parking lot is rectangular. The length is 20 m less than the width. The perimeter is at least 160 m. We need to find the minimum width. 2. **Define variables:** Let the width be $w$ meters. Then the length is $w - 20$ meters. 3. **Write the formula for perimeter of a rectangle:** $$P = 2(\text{length} + \text{width})$$ 4. **Set up the inequality for the perimeter:** $$2((w - 20) + w) \geq 160$$ 5. **Simplify inside the parentheses:** $$2(2w - 20) \geq 160$$ 6. **Distribute the 2:** $$4w - 40 \geq 160$$ 7. **Add 40 to both sides:** $$4w - 40 + 40 \geq 160 + 40$$ $$4w \geq 200$$ 8. **Divide both sides by 4:** $$\frac{4w}{\cancel{4}} \geq \frac{200}{\cancel{4}}$$ $$w \geq 50$$ 9. **Interpretation:** The width must be at least 50 meters to satisfy the perimeter condition. **Final answer:** The minimum width is 50 m. Therefore, the correct choice is **b) The minimum width is 50 m**.