Brain Teasers

1. Geetha was baking biscuits and suddenly found her ring missing. She had baked 9 biscuits in that batch so she knew that the ring must have fallen in to one of them. She doesn't want to crumble up all the biscuits but she certainly does not want to lose her ring. She has a weighing machine but no weights. How can she find the ring? What is the smallest number of times she needs to use the weighing machine in order to find the ring-biscuit?

2. Knights and Knaves is a type of logic puzzle devised by the famous logician Raymond Smullyan. On a fictional island, all inhabitants are either knights or knaves. Knights always tell the truth, while knaves always lie.
	The puzzles involve a visitor to the island who meets John and Bill, both residents of the island.
	John says: We are both knaves.
	Question : Is John a knight or a knave? Is Bill a knight or a knave?
	Here is perhaps the most famous of this type of puzzle: John and Bill are standing at a fork in the road. You know that one of them is a knight and the other a knave, but you don't know which. You also know that one road leads to Death, and the other leads to Freedom.
	Question : By asking one yes/no question, can you determine the road to Freedom? By asking one yes/no question, can you determine whether John is a knight?