Final answer:
Sofia's walking speed is denoted as w km/h, so her driving speed is 15w km/h. After setting up and solving the equation for the total travel time, we find that her walking speed is 3.333 km/h and her driving speed is 50 km/h.
Step-by-step explanation:
To solve this problem, we need to find Sofia's driving speed knowing that her driving speed is 15 times her walking speed and that she drove 45 km and walked 2 km in a total time of 1.5 hours.
Firstly, let's denote Sofia's walking speed as w km/h. Therefore, her driving speed is 15w km/h.
The time taken to drive 45 km is obtained by dividing the distance by the driving speed, which gives 45 km / (15w) hours. The time taken to walk 2 km is 2 km / w hours. The sum of these two times equals the total time, 1.5 hours:
45 km / (15w) + 2 km / w = 1.5 hours
Multiplying through by w to clear the denominators, we get:
3 km + 2 km = 1.5w hours
5 km = 1.5w hours
Dividing by 1.5 hours, we find that w = 5 km / 1.5 hours = 3.333 km/h.
Therefore, Sofia's driving speed is 15 times her walking speed, which is 15 * 3.333 km/h, which equals 50 km/h.
Sofia's driving speed was 50 km/h.