You have two strings whose only known property is that when you light one end of either string it takes exactly one hour to burn. The rate at which the strings will burn is completely random and each string is different.

How do you measure 45 minutes?

Two boys were admitted to a school. When the headmaster asks them about their parents, they tell him that they have same parents (father and mother). On further inquiry, it turns out that they both share the same date for their birthday.

"Are you twins," ask the headmaster.
"No," replies the boys.

Is it possible?

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.

There is an English word that can be used up to four times in a row without modifying the spelling and form a valid grammatical sentence.

Do you know what word is that?

I am the one who remains awake when you sleep. But I need to rest when you awake. Who Am I?

What do you call a fish without an eye?

How much will a 38° angle measure when looked at under a microscope that magnifies ten times?

Decode below three cipher riddles:

26 L of the A
7 D of the W
1000 Y in a M

Can you count the number of lines in the below picture?

Luis Garavito killed Density x Volume.

Who is Luis Garavito ?