You walk into a room that contains a match, a kerosene lamp, a candle and a fireplace. What would you light first?

You have to put a letter on the following to make it a meaningful word. The only challenge is that you can't use 'E'.

S E Q U E N C _

How can you make the following equation true by drawing only one straight line: 5+5+5=550 ?

You are trapped in a room with two doors. One leads to certain death and the other leads to freedom. You don't know which is which.
There are two robots guarding the doors. They will let you choose one door but upon doing so you must go through it.
You can, however, ask one robot one question. The problem is one robot always tells the truth, the other always lies and you don't know which is which.
What is the question you ask?

Christina has four daughters, and each of her daughters has a brother. How many children does Christina have?

I have one of the three numbers: 1, 2, or 3 in my mind. I speak only truth. You can ask me just one question for which I will only reply in yes or no or don't know. What question will you ask from me so that you are able to know the number?

I am white when I am dirty, and black when I am clean. What am I?

what does this picture(rebus) riddle means ?

What goes up but never comes down?

If eleven plus two equals one, what does nine plus five equal?