In the problem, "A woman leaves her house at 6:03 am and travels 439 miles," what should students determine first to find her speed?

To find the speed of the woman traveling 439 miles, the first determination that students should make is the total time spent driving. Speed is defined as the distance traveled divided by the time taken to travel that distance. By calculating the time it took her to cover the distance, students can then use the formula for speed (speed = distance / time) to find the answer.

The total distance traveled is important but does not address the need for time, which is essential for calculating speed. The speed limit on the route provides a maximum speed but does not help in determining the actual speed without additional information on how long she traveled. Knowing the number of gas stations along the way does not directly contribute to calculating speed either, as it does not provide meaningful data relative to distance or time spent driving. Thus, focusing on the total time spent driving is crucial for solving the problem correctly.