To determine the constant of variation, we first need to understand the relationship being described in the problem. Typically, in these types of questions, the constant of variation (often referred to as k) represents the rate at which one variable changes in relation to another.

From the context of the question, it looks like we are dealing with a relationship where distance is proportional to time, which suggests that the constant of variation would be the speed of the bus in miles per hour. This means that if the distance traveled varies directly with time, the constant of variation would be the bus's speed.

However, to solve this completely, we need the specific numbers (distance and time) that are likely given in the broader problem. Could you provide those values, or let me know if there are more details about the relationship between distance and time?

Once we have those numbers, we can:

1. Divide the distance by time to find the constant of variation (speed).
2. Interpret it as the number of miles the bus travels per hour.

Would you like to provide more details?

Here are some follow-up questions related to this concept:

1. What is direct variation, and how does it differ from inverse variation?
2. How is the constant of variation used in real-life problems like this?
3. If the distance is 120 miles and the bus takes 2 hours, what is the constant of variation?
4. How can you interpret a constant of variation in a graph of distance vs. time?
5. What would happen to the constant of variation if the time increased but the distance remained the same?

Tip: In direct variation problems involving distance and time, the constant of variation is typically the speed. Always look for units like "miles per hour" to guide your interpretation.