Can you arrange four 9's and use at most 2 math symbols, to make the total 100?

John was driving a bus and got stuck when passing through an underpass. Then came Jacob with a needle and got the bus out of the underpass.

What did the boy do?

There are people and strange monkeys on this island, and you can not tell who is who (Edit: until you understand what they said - see below). They speak either only the truth or only lies.
Who are the following two guys?
A: B is a lying monkey. I am human.
B: A is telling the truth.

A word I know has six letters it contains, remove one letter and 12 remain. What is it?

Christina is practising her dance steps along with her friends. In a particular sequence, all of them form a row. At that point, Niharika is standing in the 4th position from either end of the row.
Can you find out how many girls are practising together?

A girl was standing near the window thinking something. All of a sudden she decides something and throws something out of the window. She dies very soon after throwing it. She was perfectly healthy and had no disease or allergy. No one killed her and she did not commit suicide.

Can you think of any possible explanation that is logical as well for what happened there?

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

Always in you, Sometimes on you;

If I surround you, I can kill you.

What am I?

The Little ant seems to be always confused. Do you know why?

You walk into a room that contains a match, a kerosene lamp, a candle and a fireplace. What would you light first?