Can you replace the question mark with the correct number?

Why is a river so rich ?

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?

I am the beginning of everything, the end of everywhere. I'm the beginning of eternity, the end of time and space. What am I?

You are a thief and you are being punished for your crime. People have tied your head down on a tree with a rope that has been anchored in the ground. A candle is burning below the rope which is slowly burning it away. Just below your head, a Lion has been left loose and is waiting for you to drop down on the ground so he can have you as his lunch.

You have to survive the scenario. How will you do it?

What is the four-digit number in which the first digit is one-third the second, the third is the sum of the first two, and the last is three times the second?

Christina has four daughters, and each of her daughters has a brother. How many children does Christina have?

No one wants to have it, but if one got it, he does not want to lose it. What is It?

My location can be determined by the below rebus.
So where am i ?

Find the hidden panda in the image below.