Passage Summary: At this car lot, new cars are expensive and old cars are cheap, so anything in the middle price range must be a relatively recent used car.

Conclusion: Cars priced between $5,000 and $18,000 must be used vehicles less than ten years old.

Reasoning: New cars are all priced above $18,000, and cars ten years or older are all priced below $5,000.

Analysis: The logic here is a simple 'middle-out' elimination. If a car is not in the 'expensive/new' bucket and not in the 'cheap/ancient' bucket, it must be in the 'moderate/recent' bucket. This structure relies on the fact that the two premises cover the only ways a car could be 'new' or 'very old.' We want an answer that carves out two ends of a spectrum to define what is left in the center.