A couple has two children. At least one of them is a boy. Assuming the probability of having a boy or girl is 50%, what is the probability that both children are boys?
If you answered 1/2, you’re not without comrades, but the generally accepted answer by statisticians (though not without debate) is 1/3. This is because there are four possible combinations: boy-boy, boy-girl, girl-boy and girl-girl. Since we are told one of the children is a boy (but we don’t know if it’s the first or second child), we can rule out the girl-girl combination, leaving three remaining options. Only one out of 3 is boy-boy, so we get a 1/3 chance.
I am two-faced, but bear one head.
Men spill their blood for me.
I have no legs but travel widely.
I make kings immortal.
I am potent when shared,
Yet lust for my power keeps me locked away.
Money (coins specifically). Coins have two faces, heads and tails. People fight for money, and money travels far and wide. Kings live on when they’re depticted on a coin. Sharing money with others is a meaningful experience yet many people keep their money locked up.
Cornelius got a flat tire on a miserable, rainy day. As he was changing it on the side of the road, he placed the four lug nuts in the overturned hub cap. As our dear friend was moving back to put on the spare, he accidentally bumped the hub cap. He watched helplessly as all four lug nuts rolled into a deep sewer and were whisked away. Then our friend had a brilliant solution and within minutes was driving safely away.
A fish. A fish bowl or aquarium is the fish’s house and the people inside are the decorative divers that offer no reply (one might ask how the fish knows, given that they aren’t a talkative bunch themselves).