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

Why is 6 afraid of 7?

John is selling fruits.
He sells grapes at $30, Dates $25, and a Wolfberry $45.
At what price does he sell fig?

PS: Logical Thinking

How many times do a clock's hands overlap in a day ?

Railroad Crossing, look out for the cars. Can you spell that, without any R's ?

There was a minor accident with a doctor's son but the doctor noticed no major injury. After the treatment, the father of that doctors son is sitting with the son of the doctor without the doctor being in the room.

How can this be possible?

Before reading ahead, you must know the fact that only one of the people here is telling the truth.

A says that B is lying.
B says that C is lying.
C says both A and B are lying.

Can you find out who is speaking the truth?

Assume there are approximately 5,000,000,000 (5 billion) people on Earth. What would you estimate to be the result, if you multiply together the number of fingers on every person's left hand? (For the purposes of this exercise, thumbs count as fingers, for five fingers per hand.) If you cannot estimate the number then try to guess how long the number would be.

In a university, a professor gave a set of three problems to the three brilliant students of his class. See the image for the questions.

Prove that twice of ten is the same as twice of eleven.