What is the longest word in the dictionary?

How can a man go eight days without sleep?

Find the missing number in the image below.

A high school has a strange principal. On the first day, he has his students perform an odd opening day ceremony:

There are one thousand lockers and one thousand students in the school. The principal asks the first student to go to every locker and open it. Then he has the second student go to every second locker and close it. The third goes to every third locker and, if it is closed, he opens it, and if it is open, he closes it. The fourth student does this to every fourth locker, and so on. After the process is completed with the thousandth student, how many lockers are open?

A girl rode into a tourist spot out of the city on Thursday. She loved the place and decided to stay for a few days. She stayed for four days and then she left for back home on Thursday.

How can this be possible?

Can you make the below equation true by using any three numbers from "1, 3, 5, 7, 9, 11, 13 and 15"?

( ) + ( ) + ( ) = 30

What have one eye but still cannot see?

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

Quickly Solve this riddle

7 - 4 + 3 * 0 + 1 = ?

Is the statement valid that it does not matter how much older a sibling is, eventually the younger one will be half as old as the older one?