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

What is the four-digit number in which the first digit is one-third the second, the third is the sum of the first two, and the last is three times the second?

One absent-minded ancient philosopher forgot to wind up his only clock in the house. He had no radio, TV, telephone, internet, or any other means for telling time. So he travelled on foot to his friend's place a few miles down the straight desert road. He stayed at his friend's house for the night and when he came back home, he knew how to set his clock. How did he know?

what's the probability of getting a king or a queen from a pack of 52 cards?

You see a mathematical expression in the picture. Can you think of a movie that this expression refers to?

Can you count the number of squares in the given picture?

What do you see in the image below

John is asked to stand behind Jacob and Jacob is asked to stand behind John. Both of them feel confused about it and don't know what to do?

But it is quite possible, do you know how?

John named his first son Alpha, second Beta, third Charlie and fourth Delta. What is the fifth son's name?

What always comes into a house through the keyhole?