i found the ans in 30 mins but dont know correct or not?公仔箱論壇. n3 N4 i" }- |
ans is too long! but concepts are something like that:; R! M j8 Y& M
seprate 4 groups 3 balls in one group! tvb now,tvbnow,bttvb( r. D' r5 b( r* n1 f" q
the 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!
8 L, C# a, ?7 |6 k# jthe last part is 1ball vs 1ball! something like that |