You have 100 bags of coins each with 100 coins, but only one of these bags has gold coins. The gold coin weighs 1.01 ounce and the other coins weighs 1 ounce. You also have a scale, but can only use it once. How can you identify the bag of gold coins?
Is buying 2 U.S. $50 1oz gold coins for $700/each a risk?