i thing the answer is
+ U8 r, C; |5 |/ Nstart with 4 on each side of the scale,this will have two possible outcome, same or diff.
5 r$ c9 s# O* |( ]. P5 f i# WIf the same then 4 that left over contain the odd ball. put 1 of the 4 to each side, two outcome, same or different again. Replace 1 from the remaining, if the same then left over is the odd or if different the replacement is the odd one. I didn't time myself but I think I take less than 30 minutes. There are two more possible out come but still need three weighing but I think I am running out of space. |