To determine how many trips Scott needs to make in total to walk 10 kilometers, we first calculate the distance he walks in each trip.
Since Scott made 2 trips to school and walked a total of 4 kilometers, we can find the distance per trip:
\[ \text{Distance per trip} = \frac{\text{Total distance}}{\text{Number of trips}} = \frac{4 \text{ km}}{2 \text{ trips}} = 2 \text{ km/trip} \]
Next, we need to find how many trips Scott needs to make to reach a total of 10 kilometers. To do this, we set up the following equation:
\[ \text{Total trips} = \frac{\text{Total distance}}{\text{Distance per trip}} = \frac{10 \text{ km}}{2 \text{ km/trip}} = 5 \text{ trips} \]
Thus, Scott will need to make 5 trips in total to walk a total of 10 kilometers.