why number 8549176320 is one of a kind?

I am white when I am dirty, and black when I am clean. What am I?

The centre of the third figure is empty. What digit should fit inside?

I am a normal creature, but I have five hands. I can even have more but even then I will be considered normal.

Who am I?

What is always in front of you but can’t be seen?

I shave every day, but my beard stays the same. What am I?

You may enter, but you may not come in. I have space, but no room. I have keys, but open no lock. What am I?

All of Jacob's shoes are red except two.
All of Jacob's shoes are green except two.
All of Jacob's shoes are yellow except two.

How many shoes does Jacob have?

Divide 110 into two parts so that one will be 150 per cent of the other. What are the 2 numbers?

Imagine a box with two cogwheels, one big with 24 teeth and one small with 8 teeth. The big one is firmly attached to the center of the box which means it does not turn or move while the small one rotates around the big one.

How many times do you think that the smaller wheel will turn compared to the box when it turns once around the big one?