i thing the answer is8 m- h' `% C f$ \: B( W7 N- J8 I2 ^! C
start with 4 on each side of the scale,this will have two possible outcome, same or diff.公仔箱論壇 [ g" n) t! G" E* P7 o. f+ z" _
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. |