2. Just about three hours in a plane. (Okay, or 100 days walking, but the riddle didn’t specify that he was walking – just that he can walk two miles per hour.)

3. A volcano.

4. “Fluoridation” has 12 letters, and some dictionaries carry “fluoridization,” with 14 letters, as a synonym. The word “duotrigintillion” is in some English dictionaries. It is the name for a very large number (10 to the 99th power), and it has 16 letters.

5. He climbed into the landing gear of a plane to get a free ride, and the temperature at 30,000 feet was 40 degrees below freezing.

6. I said that,”that ‘that’ that that man wrote should have been underlined. For a complete explanation, see the page;