Can you solve this amazing hard number series problem?
7, 8, 10, 12, 16, 18 ?

Three friends named Mr. Black, Mr. Yellow and Mr. Green enter a pub on a weekend night. They are wearing either a Black, Yellow or Green shirt.

Mr. Yellow says to them, 'Did you notice that we all are wearing different color shirts than our names?'

To this, the man who was wearing the Green shirt said. 'Wow, thats right.'

Can you identify who is wearing which colour shirt ?

Assume the given figure to be a delicious doughnut. Yes, now you can concentrate more on the puzzle. So you have this delicious doughnut in your refrigerator when your friends come knocking at the door. There are eight of them. Now you have to make three cuts in this doughnut so that each one of you nine people can enjoy a piece of it. Neither you nor your friends would mind the size of their piece as long as they are getting it. How will you do it?

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?

What is so fragile that saying its name breaks it?

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

Why do people go to bed?

There are three houses in a straight row. One is red, one is blue, and one is white. The red house is left of the middle. The blue house is right of the middle. Where's the white house?

John replied, when asked how old he was. In 2 years he will be twice as old as he was five years ago.' How old is he ?

I am not alive, but I grow; I don't have lungs, but I need air; I don't have a mouth, but water kills me. What am I?