Math Quiz: NYT Learning Network

Through Math for America, I am part of an on-going collaboration with the New York Times Learning Network.  My latest contribution, a Test Yourself quiz-question, can be found here:

Test Yourself Math — October 22, 2012 

This question has to do with Felix Baumgartner’s recent skydive from 23 miles above the Earth’s surface.  What was his average speed during free fall?