There are 15 gold coins. One of the gold coins is a fake. A fake gold coin is lighter than a real one. You have a “balance machine” without any scale. Can you identify the fake coin by using the “balance machine” at most three times?
+36915 Yes you can....is that what you wanted.....or an explanation as to how?
Starts this way make 3 piles 7 7 1
balance the 7's if they balance, then the '1' is the fake
if they DON't balance, the lighter 7 has the fake
take the lighter 7 make 3 piles 3 3 1
balance the 3's if they balance then the '1' is the fake
if they don't balance then the lighter 3 has the fake
take the lighter 3 make 3 piles 1 1 1
balance two of the 1's
if they balance , the third '1' is the fake
if they don't balance , the lighter one is the fake .....with only THREE balances done !
+36915 Yes you can....is that what you wanted.....or an explanation as to how?
Starts this way make 3 piles 7 7 1
balance the 7's if they balance, then the '1' is the fake
if they DON't balance, the lighter 7 has the fake
take the lighter 7 make 3 piles 3 3 1
balance the 3's if they balance then the '1' is the fake
if they don't balance then the lighter 3 has the fake
take the lighter 3 make 3 piles 1 1 1
balance two of the 1's
if they balance , the third '1' is the fake
if they don't balance , the lighter one is the fake .....with only THREE balances done !
