What mathematical symbol can be put between 5 and 9, to get a number bigger than 5 and smaller than 9?

I know a nine-letter word having only one vowel.
Do you ?

When Jack was six years old he hammered a nail into his favourite tree to mark his height. Ten years later at age sixteen, Jack returned to see how much higher the nail was. If the tree grew by five centimetres each year, how much higher would the nail be?

What can run but never walks, has a mouth but never talks, has a head but never weeps, has a bed but never sleeps?

First, think of the colour of clouds. Next think the colour of snow. Last, think of the colour of the moon. Now, what do cows drink?

What is the unique property of the following words ?
* Revive
* Banana
* Grammar
* Voodoo
* Assess
* Potato
* Dresser
* Uneven

This is the oldest riddle that I have heard.

Once there was a man who was travelling with a Tiger, goat and grass.
He needs to cross a river that can carry a maximum of two i.e. Man + one of Tiger goat or grass. But the problem is "If he takes the lion with him, the goat will eat grass and if he takes grass with him, the lion will eat the goat".

How can he ensure the safe delivery of all three?

A prisoner is told: "If you tell a lie, we will hang you and if you tell the truth, we will shoot you." What did the prisoner say to save himself?

A girl was sitting in her hotel room when she heard a knock on the door. She opened the door and found that a man was standing outside. The man said, "Oh! I am really sorry, I thought this was my room." He then walked through the corridor to the elevator. The girl did not know the man. She closed her door and called security asking them to apprehend the man. What made her suspicious of that man? He might have been genuinely mistaken.

If 21x = 79x, what is the value of x?