Find the missing number in the sequence below:

You have two strings whose only known property is that when you light one end of either string it takes exactly one hour to burn. The rate at which the strings will burn is completely random and each string is different. How do you measure 45 minutes?

John went to meet his friend Jacob, but when he was about to reach the main gate, John notices that Jacob had a mighty dog who was fastened to the tree. The chain is long enough that it allows the dog to reach the main gate.

How can the John reach the main gate?

Which is heavier: a ton of bricks or a ton of feathers?

A man and a dog were going down the street. The man rode, yet walked. What was the dog’s name?

Can you count the number of triangles in the given picture?

A woman lives in a skyscraper thirty-six floors high and is served by several elevators which stop at each floor going up and down. Each morning she leaves her apartment and goes to one of the elevators. Whichever one she takes is three times more likely to be going up than down. Why?

They are the five precious gems of an everyday sort and all can be found on a Tennis Court. Who are they?

Two in a corner, one in a room, zero in a house, but one in a shelter. What am I?

I add 5 to 9 and get 2. The answer is correct, so what am I?