Final answer:
Adam will have driven 80 kilometers after 4 hours.
Step-by-step explanation:
To determine the distance Adam will have driven after 4 hours, we need to use the information provided in the double number line. If we know Adam's constant rate, we can use the ratio on the double number line to find the distance for a given time.
Let's assume that Adam's rate on the double number line is 20 km/h. If we look at the ratio on the double number line, we can see that for every 1 hour, Adam travels 20 kilometers.
Therefore, after 4 hours, Adam will have driven 4 times 20 kilometers, which equals 80 kilometers.