Well..divided into 6/6 first to define a heavier group is certainly right. Randomly select 3/3 will result another heavier group. & a( P+ Z# u# o" D w公仔箱論壇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. 8 X" {/ L) {9 m5 P. q- S& S! atvb now,tvbnow,bttvb