What happened when the wheel was invented?

There is a square piece of paper with a hole that is denoted by the circle on the top right side in the given picture. You have to cut the paper in a manner that it forms two and only two separate pieces of paper and then rearrange the pieces in a manner that the holes come in the centre of the paper.

Count the number of triangles in the below picture?

A man desired to get into his work building, however he had forgotten his code.
However, he did recollect five pieces of information
* Fifth number + Third number = 14
* The fourth number is one more than the second number.
* The first number is one less than twice the second number.
* The second number and the third number equals 10.
* The sum of all five numbers is 30.

What is the code ?

If your uncle’s sister is not your aunt, what relation is she to you?

There was a minor accident with a doctor's son but the doctor noticed no major injury. After the treatment, the father of that doctors son is sitting with the son of the doctor without the doctor being in the room.

How can this be possible?

You can see it everyday, But cannot touch it at will. What is it?

How many pluses should we put between the digits of 987654321 to get a total of 99, and where?

Here is a mathematical expression that also secretly tells a movie name. What movie is that?

When you say goodbye, I am what you need to tie.
I come as a couple and go wherever you run.
Who am I?