I received the following from a friend who teaches statistics at a small liberal college on the East Coast:
On his most recent exam, he asked students: "Estimate how long it would take to fly around the world in a hot air balloon."
The response from one student: "The estimated length of how long it would take to travel the whole world in a hot air balloon depends on weather conditions. Therefore, I will add 2 days to the result due to severe weather conditions. To travel in a plane across the whole world it would take about 7 days, however, a hot air balloon's speed is a lot smaller than an airplane. Therefore, I believe it will take the hot air balloon three times more days than an airplane to travel the entire world. After multiplying seven to three and adding two days (due to weather conditions), the result is 21 days to travel across the world in a hot air balloon."
Special weblog contest #9:Estimate the number of different ways and levels in which this answer is incorrect. Closest guess wins a limited edition JFW kewpie doll.