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: Just 2.
Each time you give the owner of a bridge half of your brownies (1 brownie) they give you one back as well.
Question: In a house of Kardak's family each brother have a sisters as double as their brothers and each sister have brothers as same as their sister. How many brothers and sisters in Kardak's family ?
Answer: 3 brothers and 4 sisters