I have no doors but I have keys, I have no rooms but I have space, you can enter but you can’t leave! What am I?

John has eleven friends. He has a bowl containing eleven apples. Now He wants to divide the eleven apples among his friends, in such a way that an apple should remain in his bowl.
How can He do it?

I can write cow in 13 letters.

Can You?

When I got four, I have it none.
When I got two, I have it some.
When I got none, I have it all.

What is it?

Without looking at a calendar, within a minute name, a boy's name using 5 consecutive 1st letters of 5 consecutive months

I was born in a small house and I live in it all alone. No windows and no doors have been assigned to my house. The only way I can go out is by breaking through the walls of my house.

Who am I?

What's the best place to go shopping in the ocean?

I have teeth but i don't bite. Who Am I ?

Take away my first letter, then take away my second letter. Then take away the rest of my letters, yet I remain the same. What am I?

A convention is held where all the big logicians are summoned. The master places a band on everyone's forehead. Now all of them can see others bands but can't see his own. Then they are told that there are different colours of bands. All the logicians sit in circle and they are further explained that a bell will ring at regular intervals. The moment when a logician knew the colour of band on his forehead, he will leave at the next bell. If anyone leaves at the wrong bell, he will be disqualified.

The master assures the logicians that the puzzle will not be impossible for anyone of them. How will the logicians manage ?