problem with doubles

[Michael P.]

So I've attached the file for a very simple program I'm working on.
The problem comes from past contests questions, see this:

http://www.cemc.uwaterloo.ca/ccc/past/previous_contests.shtml

The problem I've having is with 2008 Junior problem 1. Every time with my code it says you are overweight, when it is supposed to say normal weight.
So I tried printing out the value I was comparing, and it said nan. Anyone know why?
-Michael P.
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