When I get multiplied by any number, the sum of the figures in the product is always me. What am I?

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?

Samuel was out for a walk when it started to rain. He did not have an umbrella and he wasn't wearing a hat. His clothes were soaked, yet not a single hair on his head got wet. How could this happen?

A new Engineering building containing 100 offices had just been completed. John was hired to paint the numbers 1 to 100 on the doors. How many times will John have to paint the number nine (9)?

The dirtier I get, the whiter I look. Who am I?

It can be easily calculated that the digits 0 to 9 can be arranged into 3628800 distinct ten-digit numbers.

But do you know how many of these numbers are prime?

Can you find the missing piece of the Porsche?

I live in a bowl. I can swim. I have a tail. I also have fins and big eyes. What am I?

I have a big mouth and I am also quite loud! I am NOT a gossip but I do get involved with everyone's dirty business.

What have one eye but still cannot see?