i thing the answer is
5 M* D8 c3 z9 G S( A公仔箱論壇start with 4 on each side of the scale,this will have two possible outcome, same or diff.
' Z0 }( V. E9 F/ ]+ u! F5 FIf 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. |