Puzzle: On Bagshot Island, there is an airport. The airport is the home base of an unlimited number of identical airplanes. Each airplane has a fuel capacity to allow it to fly exactly 1/2 way around the world, along a great circle. The planes have the ability to refuel in flight without loss of speed … Read More →
Red and Blue Balls in a Bag
Problem: You have 20 Blue balls and 10 Red balls in a bag. You put your hand in the bag and take off two at a time. If they’re of the same color, you add a Blue ball to the bag. If they’re of different colors, you add a Red ball to the bag. What … Read More →
Squares on a chess board?
Problem: How many squares are on a chess board? If you thought the answer is 64, think again! How about all the squares that are formed by combining smaller squares on the chess board (2×2, 3×3, 4×4 squares and so on)? A 1×1 square can be placed on the chess board in 8 horizontal and 8 … Read More →
Boys and Girls
Question: In a country where everyone wants a boy, each family continues having babies till they have a boy. After some time, what is the proportion of boys to girls in the country? (Assuming probability of having a boy or a girl is the same) Answer: “very simple”. Half the couples have boys first, and … Read More →
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