Two people have asked you out for a date and you’ve decided to decide who to go with by flipping a coin. The problem is that the only coin you have is biased: you know that heads comes up with a probability of rather than as is the case with a fair coin. However, you do really want each of the two people to have a fair chance of being picked. Using a combination of two coin flips instead of one, can you find a way of making the random decision fair?
(Hint: the chance doesn't have to be 50:50.)