the diffeent coin

Weigh 150 against 150 with 66 left over. If they balance, select last pile, if one tips heavier, select that one.

Assume latter

three piles of 50, weigh first two against each other.

repeat like this, do in 6 steps.

150,150,66
50,50,50
20,20,10
7,7,6
2,2,3

How do you know the odd coin is heavier?

It can be done with 364 coins if you don't have to determine if the odd coin is heavier or lighter. It can be done with 363 coins if you do have to make that determination.

Here are two good sites:
http://www.iwriteiam.nl/Ha12coins.html
http://rec-puzzles.org/sol.pl/logic/weighing/balance

Thats a good question mark, to be honest I just assumed it would be because in thes type questions it usually is. I didn't pay enough attention to the way it was worded.

i don't know the answer
but thanks marker to relieve my stress for trying to solve it