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:

https://learning.blogs.nytimes.com/2011/11/30/test-yourself-math-nov-30-2011/

This problem is related to the increase in on-line education services being offered by established colleges and universities.  How much money is there to be made in this business?