1. **State the problem:** Sofia drove 45 kilometers and then walked 2 kilometers to a gas station. Her driving speed is 15 times her walking speed. The total time for driving and walking is $1\frac{1}{2}$ hours (which is $1.5$ hours). We need to find Sofia's driving speed. 2. **Define variables:** Let $w$ be Sofia's walking speed in km/h. Then her driving speed is $15w$ km/h. 3. **Write the time equations:** Time = Distance / Speed. - Driving time: $\frac{45}{15w} = \frac{45}{15w} = \frac{3}{w}$ hours. - Walking time: $\frac{2}{w}$ hours. 4. **Total time equation:** Driving time + Walking time = Total time $$\frac{3}{w} + \frac{2}{w} = 1.5$$ 5. **Simplify the equation:** $$\frac{3+2}{w} = 1.5$$ $$\frac{5}{w} = 1.5$$ 6. **Solve for $w$:** $$w = \frac{5}{1.5} = \frac{5}{\frac{3}{2}} = 5 \times \frac{2}{3} = \frac{10}{3} \approx 3.33 \text{ km/h}$$ 7. **Find driving speed:** $$15w = 15 \times \frac{10}{3} = 50 \text{ km/h}$$ **Final answer:** Sofia's driving speed was $50$ km/h.