I have teeth but i don't bite. Who Am I ?

In particular commonwealth games, a female participant won silver and gold medals for a single event.

How can this be possible?

On a magical land of Mexico , all the animal in the land are rational.

There are 10 tigers and one goat.
Tiger can eat goat but since it's a magical land , the tiger who eats the goat , turns into goat and then can be eaten by the remaining tiger(s).

If we leave them for some time then how many goat and tiger will be there , when we come back ?

What can run but never walks, has a mouth but never talks, has a head but never weeps, has a bed but never sleeps?

It walks on 4 when its young, walks on 2 when it's older, and walks on 3 when its very old?

P is the father of Q and S is the son of R. T is the brother of P and has a daughter U. If R is the sister of P, then what is the relation between U, Q and S?

Things are just as they seem, right? Well, check again.
Can you count the number of tigers in this picture ?

John is asked to stand behind Jacob and Jacob is asked to stand behind John. Both of them feel confused about it and don't know what to do?

But it is quite possible, do you know how?

Keyboard words are not in alphabetical order, Why?

Trying to tease Birbal, Akbar gave him one gold coin and ask him to buy
* something for him to eat
* something for him to drink.
* something to feed the cows
* something to plant in the garden
and most important you need to buy only one thing.

What must Birbal buy to silence Akbar?