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: Leap Year is every 4 years. True or False ?
Answer: False. Every year that is exactly divisible by four is a leap year, except for years that are exactly divisible by 100, but these centurial years are leap years if they are exactly divisible by 400. For example, the years 1700, 1800, and 1900 are not leap years, but the years 1600 and 2000 are. So 3 out of every 400 years are not leap years.