Help help its urgent this problem needs to be solved or else i die im not cheating homework
4 small bars are supposed to be gold, one of them is counterfeit. Counterfeit one is different from the other ones. Using a balance scale, what is the minimum number of weighings necessary to determine that the counterfeit bar will be detected?
Your question states the counterfit one weighs 'different' .....if you do not know in what manner the counterfit one weighs 'different' (i.e. it could weigh MORE than gold ....maybe depleted uranium or something) , then the minummwould be as follows:
split the bars up two per side.......One side will be DIFFERENT......
One side split up will be either: =.......we know those are both genuine (second weighing)
0r not = (means the other two were genuine)
third weighing with a genuine one and one from the second pair if = both genuine and the other from the second pair is counterfit
if not = then this one is cfit
Sooooo.... it will take THREE weighings if you do not know how the counterfit bar differs from the others (heavier or lighter)