Question: You’re going to a friends house and want to give them some brownies. On the way to their house, you cross 5 bridges. At each bridge, you must pay a toll of half of your brownies to the owner. But they are all very nice and give you back a brownie from what you give them. How many brownies must you start with to give your friend 2 brownies?
Answer: The answer is just 2. Each time you give the owner of a bridge half of your brownies (1 brownie) they give you one back as well.