An ordered triple of real numbers

(a,b,c) is called friendly, if each
number is equal to the product of
the other 2. How many friendly
triples are there?
Details and assumptions
The numbers need not be equal to
each other.
The numbers need not to be
pairwise distinct (which
means that no two of them
are the same). I got 31 but it isn't
right ...

2 answers

brilliant na??

stuck on that one also :((