Luis Garavito killed Density x Volume.

Who is Luis Garavito ?

Use only one mathematical symbol and all numbers (0-9) to get a sum of 99

What is always in front of you but can’t be seen?

During which month do people sleep the least?

A man stands on one side of a river, his dog on the other. The man calls his dog, who immediately crosses the river without getting wet and without using a bridge or a boat. How did the dog do it?

Three people are in a room. Ronni looks at the Nile. The Nile looks at Senthil. Ronni is married but Senthil is not married. At any point, is a married person looking at an unmarried person? Yes, No or Cannot be determined.

Can you spot the hidden girl in the picture below?

I am thinking of a five-digit number such that:
The first and last digits are the same, their submission is an even number and multiplication is an odd number and is equal to the fourth number. Subtract five from it and we obtain the second number. Then divide into exact halves and we get the 3rd number.

What number I am thinking of?

You knock a Table over in the library, and suddenly 20 eyes are looking at you.

A certain street contains 100 buildings. They are numbered from 1 to 100. How many 9's are used in these numbers?