Using the clues below, what four numbers am I thinking of?

The sum of all the numbers is 31.
One number is odd.
The highest number minus the lowest number is 7.
If you subtract the middle two numbers, it equals two.
There are no duplicate numbers.

There is a straight highway. Four different villages lie on that highway. The distance between them is different. The third village is 60km away from the first village; the fourth is 40 km away from the second; the third is 10 km near to the fourth that it is to the second.

Can you calculate the distance between the fourth and the first village ?

I have cities, but no houses. I have mountains, but no trees. I have water, but no fish. What am I?

I have branches, but no fruit, trunk or leaves. What am I?

Luis Garavito killed Density x Volume.

Who is Luis Garavito ?

During which month do people sleep the least?

Twice ten are six of us,

Six are but three of us,

Nine are but four of us;

What can we possibly be?

Would you know more of us?

Twelve are but six of us,

Five are but four, do you see?

What are we?

A father's child, a mother's child, yet no one's son.

Who am I?

A maths symbol is hidden in the below Bar Graph. Can you decipher it?

Find three numbers such that

* When we multiply three numbers, we will get the prime numbers.
* The difference between the second and the first number is equal to the third and second.