P is the father of Q and S is the son of R. T is the brother of P and has a daughter U. If R is the sister of P, then what is the relation between U, Q and S?

You are trapped into a death trap by the famous jigsaw killer. As usual, a screen flashes in front of you and explains you the trap game. There are 100 pearls kept in a bowl in front of you and an empty bowl. Among the 100 pearls, 50 are white and 50 are black. You can divide them as you like into the two bowls. Once you are done, you will pull a lever, which will turn the room pitch black. The bowls will move and shuffle around. In the dark, you have to pick up one pearl from any bowl. Once you do that, the room will flood with lights again. If the peral you have in your hand is white, you will be allowed to live, but if the pearl you picked is black, the room will be filled with poisonous gas and you will die. How will divide the pearls to increase your chances of survival?

John and Jacob are twin brothers. One of them is a liar whereas the other one is a truth-teller.

I called their home number and one of them picked up.
I asked. 'Does John lie?' The person replied with a yes.

Whom did I talk with, John or Jacob?

A man who was outside in the rain without an umbrella or hat didn’t get a single hair on his head wet. Why?

How many pluses should we put between the digits of 987654321 to get a total of 99, and where?

A man says, "Brothers and sisters, have I none, but that man's father is my father's son." Who is that man?

Count the number of triangles in the picture below:

There are two candles. Both will only burn exactly for an hour. How will you use these two candles to measure forty-five minutes?

It belongs to you, but other people use it more than you do. What is it?

Can you decipher the two rows to find the hidden word?