i thing the answer is
8 E: C6 j' K, \) [. E4 h* ^start with 4 on each side of the scale,this will have two possible outcome, same or diff.) O9 e; p+ M+ f- i
If 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. |