How many brownies must you start with to give your friend 2 brownies?

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 1

If you are to have two brownies at your friends house then you must have received one from the toll at the last bridge and one after giving half of what you had. So, you must have had two before giving toll at the bridge. So if you had 2 before any bridge you would land with two afterwards also, hence starting with two brownies will end in having two brownies at the end.