In a stable, there are men and horses. In all, there are 22 heads and 72 feet. How many men and how many horses are in the stable

I am a prime number.
The double of myself is equal to the square of me.

which number am I?

There is a box full of marbles,
all but two are blue,
all but two are green,
and all but two are red.

How many marbles are in the box?

When I get multiplied by any number, the sum of the figures in the product is always me. What am I?

Considering the below equation:

V + II - VI = 10
IV - X + VIII = 20
IV - VII + VI = 30

Then, I + II + III = ?

What comes
Once in a Year
Twice in a Month
4 times in a Week
6 times in a Day

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

What Am I?

A new Engineering building containing 100 offices had just been completed. John was hired to paint the numbers 1 to 100 on the doors. How many times will John have to paint the number nine (9)?

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 many times can you subtract the number 5 from 25?