Here's a riddle...

[Mean MrMustard]

I saw this on ATOT a long time ago, but I can't remember the answer.

There are 9 metal balls, 8 of them weigh the same, 1 weighs more. You have a weight scale but you only have 2 tries. How do find which one weighs more?

Craig

 

[gopunk]

divide into 3 and 3, leave 3 out

if they weigh the same, weigh 2 of the other 3

if not, take the 3 that weighs more and weigh 2 of those 3

 

[Yossarian]

It's also possible to figure it out if the different ball is either heavier or lighter.