Well..divided into 6/6 first to define a heavier group is certainly right. Randomly select 3/3 will result another heavier group.
$ K0 N0 G0 ~& w7 ^+ }The problem is we don't know the weight of each individual ball, so it will not be accurate to figure out which ball is irregular by only weight them once.
# A6 ?& L7 ?, ` |