Homonyms are words which sound the same, but are spelled differently and have different meanings. What pair of homonyms in the English language have the exact opposite meaning which means they are also antonyms.

cleave (cut/adhere)

A man is pushing his car. He stops in front of a hotel and immediately knows he is bankrupt. How did he know?

He is playing monopoly

There are 50 books on a bookshelf. Each book is two inches thick. How far is it from page one of Volume 1 to the last page of Volume 50?

Just about 96 inches, assuming the first book faces the same way as the last book, and that the covers aren't really that thick. (For example, if they are both upright with their spines facing out, then page one of the first book is actually on the inside, right next to the second book. Also, the last page of the last book is on the inside as well, next to the previous book)