What is common among 11, 69, and 88?

I organized a small get together at my home.
In the party , i have a barrel with some whiskey in it.

Suddenly Guest 1 say 'I bet this barrel of whiskey is more than half full'.
'No, it's less than half full' Guest 2 replied.

I don't have any measuring instrument and without removing whiskey from it , how can i determine which of the guest is right ?

There’s a one-story house in which everything is yellow. Yellow walls, yellow doors, yellow furniture. What colour are the stairs?

By adding four matchsticks, can you divide the square shown in the picture into two equal parts?

John decided to give his bike 3 coats of paint. Which coat would go on the first?

Suppose that you are trapped on the surface of a frozen lake. The surface is so smooth and ideal that there is no friction at all. You cant make any grip on the ice and no wind is blowing to help you out. You have just a mobile phone with you which has got no reception disabling you to call for help.

How will you plan your escape before you freeze to death on the frozen lake?

If Rajina's daughter is my daughter's mom, who am I to Rajina?

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?

How many triangles can you count in the figure given?

While handling a project, the landscaper is asked by the owner of the mansion that he wants four trees in front of his mansion that are exactly equidistant from each other.

How will he do it?