what does the below rebus means?

There are a number of books on a shelf. If one book is the 4th from the left and 6th from the right, how many books are on the shelf?

A tree doubled in height each year until it reached its maximum height over the course of ten years. How many years did it take for the tree to reach half its maximum height?

You need to move three matchsticks to form three squares. Can you do it?

Daniel walks into a movie theatre. While in the movie, he suddenly smiles delightfully. About a couple of minutes later, he seems shocked. He walks out of the theatre, goes to a bridge and jumps over the edge killing himself.

Why did he do it?

Note: Think Lateral

I am not a bull but I have horns.
I am not an ass but I have a pack saddle.
Wherever I go, I leave silver behind me.

Who am I?

There are 2 cops parked along a one-way street looking for traffic violations. They spot a taxi driver going in the wrong direction, yet they do nothing.

Why?

A mile-long train is moving at sixty miles an hour when it reaches a mile-long tunnel. How long does it take the entire train to pass through the tunnel?

Sharpest vision can find the lamp in the desert. Are you one of them? Test your observation skills now!

What month of the year has 28 days?