interesting math riddle

[bunny]

<font color="white">Make a pile of 18 random coins - there are x heads in it.
This means pile one has x heads and 18-x tails.
Pile two has 18-x heads and 32 -(18-x) tails.
If you now flip pile one it has x tails and 18-x heads.
Both piles now have the same number of heads. </font>