The extra credit problem requires real world information.  Unlike
most problems assigned in class, these will require you to first figure
out a) what is being asked, b) what information s needed to answer it,
c) where the information can be found.  I am not looking for exact
answers.  I want an 'order of magnitude'.  Is it 1 million, 10 million,
100 million, ...?  (Or in scientific notation, is it 10^6, 10^7, 10^8,
...?)

	In this problem, you might need to know how far the average
american drives each year.  You could get this from many possible sources,
including your own experience, new car warranties, used car want ads, the
web, ...  Is it 1000? 2000? 5000? 10,000? 20,000? 50,000? 100,000? 

	This is not intended as a research project so approximate numbers
are good enough.  I don't want an exact number.  The aim of these problems
is to teach you a) how to answer imprecise, nontextbook, real-world
questions and b) to understand the meaning of large numbers.