A certain street contains 100 buildings. They are numbered from 1 to 100. How many 9's are used in these numbers?

While going to your grandmother's house, you counted Twenty houses on the right side. While returning back to your home, you counted Twenty houses on the left side.

How many houses are there between your home and your grandmother's home?

What word begins and ends with an E, but has only one letter?

What is the Surname of Barbie Doll?

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?

I am weightless, but you can see me. Put me in a bucket, and I'll make it lighter. What am I?

I have no life, but I can die. What am I?

A man calls his dog from the opposite side of a river. The dog crosses the river without a bridge or a boat and manages to not get wet. How is this possible?

The Puzzle: A girl, a boy, and a dog start walking down a road.

They start at the same time, from the same point, in the same direction.

The boy walks at 5 km/h, the girl at 6 km/h.

The dog runs from boy to girl and back again with a constant speed of 10 km/h. The dog does not slow down on the turn.
How far does the dog travel in 1 hour?

What has many keys but can’t open a single lock?