galleons and cards
harry potter and draco malfoy have a fight about who will clean the hogwarts bathrooms. draco malfoy tells harry that he'll flip a galleon, and if it goes on the dragon side, harry will have to clean. He also says that he could shuffle a pile of cards and make one of them special, and if harry gets that one, harry will win. There are 20 cards in the pile and there is a 60% chance the galleon will flip on the dragon side. Which one should harry choose?
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1 solution
There is a 40% chance that Harry will win if he chooses the galleon. If he chooses the cards there is a 1/20 or 5% chance he wins. The galleon has better chances. Tricky Draco!