Final answer:
Distance and time vary directly. When the distance increases, the time also increases proportionally.
Step-by-step explanation:
Distance and time vary directly. When quantities vary directly, it means that as one variable increases, the other variable also increases proportionally.
For example, if you travel a distance of 10 kilometers in 1 hour, and you double the distance to 20 kilometers, you would also double the time to 2 hours. If you triple the distance to 30 kilometers, you would also triple the time to 3 hours.
So, in the case of distance and time, they vary directly: as the distance increases, the time also increases.