Which wheel of car does not rotate when you turn your car right?

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

I am the fastest animal but cannot climb the tree. What am I?

What can run but never walk, have a mouth that never speaks, have a head that never weeps, and have a bed but never sleeps?

My location can be determined by the below rebus.
So where am i ?

Can you find out the missing number?

? 4 5 3 5

9 5 7 10 3

What breaks yet never falls, and what falls yet never breaks?

There are 20 people in an empty, square room. Each person has full sight of the entire room and everyone in it without turning his head or body, or moving in any way (other than the eyes). Where can you place an apple so that all but one person can see it?

Why Aeroplane windows are round?

There is a square of a particular number which when doubled, becomes 7 more than its quarter.

Can you find the number?