i found the ans in 30 mins but dont know correct or not?
' k, e) @7 U f' p& K `' U# U3 xans is too long! but concepts are something like that:公仔箱論壇5 ` J, } F1 _9 Q1 C I. r. \. b
seprate 4 groups 3 balls in one group!
7 m1 N9 l; S' d a* s; H3 z- i" Fthe important part is the 2nd times which need to find out the fake ball is heavier or lighter by use the normal ball that u find at the first time!
$ o a& j# N4 f, P) a# i& qthe last part is 1ball vs 1ball! something like that |