What is the fastest way to double your money?

A certain street contains 100 buildings. They are numbered from 1 to 100. How many 9's are used in these numbers?

In an office's desk, you find a unique method that shows the current day of the month. Two numbered cubes are used to depict the current date.

Can you find out the numbers on both the cubes so that each date can be mentioned using them?

Please note that you have to use both the cubes to display any date. Thus the 1st day must be represented by 01 and so on.

Jenifer is learning to drive her car. She went down a one way lane and in the wrong direction. But she do not break any law.

How come ?

How can you make number one disappear by adding something to it?

My thunder comes before the lightning; my lightning comes before clouds; my rain dries all the land it touches. What am I?

What is the next number in this matchsticks series riddle?

What is the next number in this series?

4,12,84,3612....

Six glasses are in a row. The first three are filled with milk and the last three are empty. By moving only one glass, can you arrange them so that the full and the empty glasses alternate?

Solve the puzzle by telling what does below picture means.