Final answer:
Legally, you must drive no faster than 65mph on a freeway with that posted speed limit, despite other vehicles going faster.
Step-by-step explanation:
If you are driving on a freeway where the posted speed limit is 65mph, the legal speed you may drive is no faster than 65mph.
Even if other vehicles are traveling 70mph or faster, the posted speed limit is the maximum legal speed you can travel on that road. It's important to note that there might be a small amount of leeway due to the inaccuracy of speedometers, but exceeding the speed limit can result in receiving a traffic ticket. Law enforcement often uses radar to measure a vehicle's speed with greater accuracy, so it is advisable to adhere to the posted limits to avoid penalties.