Passage Summary: Most mail that is addressed right gets delivered quickly, but most mail in general takes a long time to get where it's going.

Reasoning: Almost all correctly addressed mail is delivered within two days unless damaged; however, the majority of all mail takes three or more days to arrive.

Analysis: We are looking for a deduction that must be true based on the tension between these two facts. If 'correctly addressed' mail is almost always fast, but 'total' mail is mostly slow, there is a massive gap that needs explaining. The only way for the majority of mail to be slow when the correctly addressed stuff is fast is if a very large portion of that mail is not correctly addressed. Look for an answer that forces a connection between the slow delivery times and the accuracy of the addresses on the envelopes.