Listen to this podcast on Duolingo (about 1 hour and 10 minutes long)  and answer these questions in about 250 words. Answer the following questions: 
1.  Identify the problems Luis von Ahn was trying to solve?
2.  List the things that motived Luis von Ahn over his entrepreneurial career?  Why? 
3.  What keeps people motivated to continue with the Duolinga app? Why? 
4.  How would you have solved the problem for the newspaper archives?