What always comes into a house through the keyhole?

A maths symbol is hidden in the below Bar Graph. Can you decipher it?

There is a place where if I stand up straight, I will still be considered sideways.

Why blonde cannot dial 911?

I have some blue and red sock in my drawer. I have a total of 4 socks. I pick 2 socks and the chance that I get a pair of red socks is 1/2.

What is the chance of picking a pair of blue socks?

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.

How can you tell a raw egg from a hard-boiled egg?

Name the three-letter word that can complete the below words?

A) L O _ _ _ E
B) E D U _ _ _ E
C) _ _ _ E R
D) _ _ _ T L E

What is the word or phrase?

Below the four parts have been reorganised. The four partitions are exactly the same in both arrangements. Why is there a hole?