There are forty elephants and they have forty-fore heads. How can this be possible?

There are people and strange monkeys on this island, and you can not tell who is who (Edit: until you understand what they said - see below). They speak either only the truth or only lies.
Who are the following two guys?
A: B is a lying monkey. I am human.
B: A is telling the truth.

How can you tell a raw egg from a hard-boiled egg?

I shave every day, but my beard stays the same. What am I?

Using Only Five 5's and any mathematical operator make sum as 37

Imagine you are in a room with no windows or doors. How will you get out?

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?

I am a white box having no key or lid.
Yet there is a golden treasure inside it.

What Am I?

Take away my first letter, then take away my second letter. Then take away the rest of my letters, yet I remain the same. What am I?

In a school, there are four subjects. Seventy percent of students study English, seventy five percent of students study Science, eighty five percent of students study Mathematics and eighty percent of students study Spanish.

Can you calculate the percentage of students that study all four subjects?