It walks on 4 when its young, walks on 2 when it's older, and walks on 3 when its very old?

Can anyone tell me a word in the English dictionary which has a silent 'z'?

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?

Peter wakes up daily to pick up his cycle and crosses the border between Spain and France daily with a bag on his shoulder. He is investigated daily by the officials but they don't find anything suspicious.

If we tell you that he is smuggling something what would it be?

If there are fifteen crows on a fence and the farmer shoots a third of them, how many crows are left?

What is the longest word in the dictionary?

There once were seven dwarfs who were all brothers. They were all born two years apart. The youngest dwarf is seven years old. How old is his oldest brother?

I look at you, you look at me, I raise my right, you raise your left. What am I?

I speak without a mouth, and hear without ears. I have no-body, but I come alive with the wind. What am I?

If you're 8 feet away from a door and with each move you advance half the distance to the door. How many moves will it take to reach the door?