Tuesday, July 8, 2008
10 Machines and 1 Weigh
You have ten machines that produce identical looking and feeling coins. Nine of the machines produce coins that weigh one ounce. However, one of the machines produces coins that weigh 0.9 ounces. You also have a scale with you (a digital scale, not the Libra kind). You can use the machines to produce any number of coins from each of them. Using only ONE weigh, how can you identify the machine with the lighter coins?
Subscribe to:
Post Comments (Atom)
1 comment:
ANSWER:
Take 1 coin from the first machine, 2 coins from the second machine, 3 coins from the third machine, etc. Weigh all the coins at once. If you are .4 ounces below a whole number, then the 4th machine has the odd weight coins. If you are .7 ounces below a whole number, then the 7th machine has the odd weight coins. Etc.
Post a Comment