If eleven plus two equals one, what does nine plus five equal?

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

I am the beginning of everything, the end of everywhere. I'm the beginning of eternity, the end of time and space. What am I?

Using four sevens (7) and a one (1) create the number 100. Except for the five numerals, you can use the usual mathematical operations (+, -, x, :), root and brackets ()

A sea diver is a real show-off. He showed everyone that he can hold his breath underwater for 15 minutes.

I went to the diver and told him that I can be underwater for double the time i.e 30 minutes.
He responded that he will give me 100$ if I would be able to do it. I won 100$.

What did I do?

Can you solve this amazing hard number series problem?
7, 8, 10, 12, 16, 18 ?

What 4-letter word can be written forward, backward or upside down, and can still be read from left to right?

From a pack of 52 cards, I placed 4 cards on the table.

I will give you 4 clues about the cards:

Clue 1: Card on left cannot be greater than the card on the right.
Clue 2: Difference between the 1st card and 3rd card is 8.
Clue 3: There is no card of an ace.
Clue 4: There are no face cards (queen, king, jacks).
Clue 5: Difference between the 2nd card and 4th card is 7.

Identify four cards?

Can you spot the man between the coffee bean in the picture below ?

In two decks of cards, what is the least amount of cards you must take to be *guaranteed* at least one four-of-a-kind?