13 decks of cards have been mixed. What is the minimum number of cards that must be taken out from the above-mixed cards to guarantee at least one 'four of a kind?

I look flat, but I am deep. Hidden realms I shelter. Lives I take, but the food I offer. At times I am beautiful. I can be calm, angry, and turbulent. I have no heart but offer pleasure as well as death. No man can own me, yet I encompass what all men must have. What am I?

What type of tree can I carry in my hand?

Three doctors said that Bill was their brother. Bill says he has no brothers. How many brothers does Bill actually have?

Count the number of triangles in the given picture.

Below toothpicks/matchsticks indicate the group of fishes moving from west to east direction. Can you make them move from east to west by just moving three toothpicks/matchsticks?

During an experiment, a guy throws a bouncy ball from a 100 feet tall building. The ball has a specific characteristic. Every time it hits the ground, it bounces up halfway.

How many bounces do you think the ball will make before it comes to a stop ?

The cream is heavier than Milk. True or False?

As easy as you can get into me, it is as hard to get out of me.

Do you know what I am?

There are nine letters in the below-given diagram. You have to form a nine-letter word using these letters.