Stage: 4 Challenge Level: 
A gambler bets half the money in his pocket on the toss of a coin, winning an equal amount for a head and losing his money if the result is a tail. He repeats this many times, each time betting half the total money he has. After $2n$ plays he has won exactly $n$ times. Has he more money, the same amount or less money than he started with?
Probability. Real world. Probability distributions, expectation and variance. Combining probabilities. Theoretical probability. Tree diagrams. Equally likely outcomes. Computer-based. Experimental probability. Conditional probability.
Published January 1998.
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