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

How can you write nineteen in a manner that if we take out one, it becomes twenty?

What is the coolest letter in the alphabet?

A wealthy man lives alone in a small cottage. Being partially handicapped he had everything delivered to his cottage. The mailman was delivering a letter one Thursday when he noticed that the front door was ajar. Through the opening he could see the man's body lying in a pool of dried blood. When a police officer arrived he surveyed the scene. On the porch were two bottles of warm milk, Monday's newspaper, a catalog, flyers, and unopened mail. The police officer suspects it was foul play. Who does he suspect and why?

I am the one who remains awake when you sleep. But I need to rest when you awake. Who Am I?

They came out at night, without being called.
They lost at day, without being stolen.
Who are they?

What do you get if you add 2 to 100 four times?

In the image given, you can find several triangles. Can you count them all?

Can you replace the question mark with the correct number in the below table sequence?

What work can one never finish?