Tough Brain Teasers

A word I know, six letters it contains, remove one letter and 12 remains, what is it?

How many letters are in alphabet?

Measure my life in hours. I serve you by expiring. I’m quick when I’m thin, slow when I’m fat. The wind is my enemy.

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

Turn Me On My Side And I Am Everything. Cut Me In Half And I Am Nothing. What Am I?

What disappears as soon as you say its name? 

I Am Heavy And Hard To Pick Up, But Backwards I Am Not. What Am I?

A Cowboy Rides Into A Town On Friday, Stays For Three Days, And Leaves On Friday. How Does He Manage This?

I have cities, but no houses. I have mountains, but no trees. I have water, but no fish.

What is seen in the middle of March and April that can’t be seen at the beginning or end of either month?

I come from a mine and get surrounded by wood. Everyone uses me at some point.

I have keys, but no locks; space and no rooms; you can enter but you can’t go outside.

What three letters can frighten a thief away?

What are the next three letters in this combination? OTTFFSS