A mother is 21 years older than her child. In exactly 6 years from now, the mother will be exactly 5 times as old as the child.
Where's the father?

What is a word made up of 4 letters, yet is also made up of 3. Sometimes is written with 9 letters, and then with 4. Rarely consists of 6, and never is written with 5.

How many bananas can you eat if your stomach is empty?

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?

What is the longest word in the dictionary?

You can see it everyday, But cannot touch it at will. What is it?

John named his first son Alpha, second Beta, third Charlie and fourth Delta. What is the fifth son's name?

Find the next number in the series

12, 20, 40, 72, 116, 172 ?

You are an expert on paranormal activity and have been hired to locate a spirit haunting an old resort hotel. Strong signs indicate that the spirit lies behind one of four doors. The inscriptions on each door read as follows:

Door A: It's behind B or C
Door B: Its behind A or D
Door C: It's in here
Door D: It's not in here

Your psychic powers have told you three of the inscriptions are false, and one is true. Behind which door will you find the spirit?

It comprises roots which nobody sees,
Much taller than those trees,
Up and up it goes,
Still it never grows?