What does this Rebus Picture mean?

What occurs twice in a week, once in a year but never in a day?

If 1+9+8=1, what is 2+8+9?

Below, you will find the mathematical proof that 10 equals 9.99999?. But is that possible or there is something wrong about it? Can you find the error?

x = 9.999999...
10x = 99.999999...
10x - x = 90
9x = 90
x = 10

John was drowned by he was not wet. How?

How many triangles are there on the puzzle below?

You have two buckets of 11 liters and 6 litres.
How can you measure exactly 8 litres?

Why did Buffon take the goal with him after every Juventus match?

A woman lives in a Tall building thirty-six floors high and 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?

We have four gears with below features=> Both Gear A and D has 60 teeth=> Gear B has 40 teeth=> Gear C has 20 teeth=> Every two minutes, Gear B makes 25 full turns.What is the relative speed of Gear A and Gear B?