A murderer is condemned to death. He has to choose between three rooms. The first is full of raging fires, the second is full of assassins with loaded guns, and the third is full of lions that haven’t eaten in 3 months.
Which room should he choose to have the best chance of staying alive?
A painter needed 3 days to paint a room. How long would it take him, working at the same rate, to paint a room twice as large (twice the width and twice the height)?
12 days because the walls would be four times as big as the first room.
If the walls are 10 ft x 10 ft, then each wall has 100 square feet. Adding the four walls makes 400 square feet to paint. Doubling the width and height of the walls to 20 ft x 20 ft means each wall is now 400 square feet, for a total of 1600 square feet to paint. 1600 ft is four times 400 square feet, thus if it took him 3 days to paint 400 square feet, it will take 12 days (or four times as much) to paint 1600 square feet.
Milton shuffled slowly along the shelves browsing books. He finally walked up to the counter and handed the girl a book. She looked at the inside cover and told him it would be $3.75. Milton handed her the money and walked away without the book. The girl watched him leave empty-handed but didn’t try to stop him. Why?
Milton was a forgetful and naughty fellow. He was summoning his courage to approach the counter to return his overdue book. The kindly lass at the counter saw the book was 15 days overdue and had accrued the egregious late fee of $3.75 (25 cents a day). Lesson learned, Milton never returned a book late again.
You’re in a build headed to the fourth floor. When you reach the second floor, you’ve gone one floor and have two more floors left, so you’re 1/3 of the way. But at the same time, you’re on the 2nd floor and have two more floors to get to the 4th floor, thus you’re halfway there.
This doesn’t work in Europe, because they typically refer to the “first floor” as the ground floor, and the first floor is one story up.
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.