What is the longest word in the dictionary?

Can you divide the below-given shape into four equal and identical pieces?

There are 20 people in an empty, square room. Each person has full sight of the entire room and everyone in it without turning his head or body, or moving in any way (other than the eyes). Where can you place an apple so that all but one person can see it?

What is black when you buy it, red when you use it, and gray when you throw it away?

In a concert, Christina is performing a dance show with her group.
At 10:00, she and her crew were dancing in an absolutely straight line. At that time Christina was standing in 4th position from both the front and back end of the row.

What was the size of her crew?

Find the next number in the series.
1 10 24 43 67 ?

I’m light as a feather, yet the strongest person can’t hold me for five minutes. What am I?

Here is a conversation between a couple who both are software professionals.

Husband: Hey! What is your date of birth?
Wife Replied Angrily: It is 591062400
Husband after doing some calculations replied, "Got It".

What is the DOB of the wife?

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?

Decode below rebus
D
N
A
T
S , D