Transform the word THINK into BRAIN while changing only one letter at a time in a manner that each of the word in the process is a real word!!!

Can you place six X (crosses) in below board without making three in a row in any way ?

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

I have an eye but still cannot see.

Who am I?

The first person saw the bridge step on it and crossed,
the second person saw the bridge did not step on it but crossed,
the third person did not see the bridge did not step on it but crossed.
Who are these people?

A word I know,
Six letters contain,
Subtract just one,
And twelve is what remains.

You enter your friend's room. He is not in his room. Although you see that on the bed there are two dogs, five cats, two giraffes and three pigs. Also, a couple of chickens and ducks are flying in the room.

Calculate the number of legs standing on the floor.

Six people park their car in an underground parking of a store. The store has six floors in all. Each one of them goes to a different floor. Simon stays in the lift for the longest. Sia gets out before Peter but after Tracy. The first one to get out is Harold. Debra leaves after Tracy who gets out on the third floor.

Can you find out who leaves the lift on which floor?

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

Count the squares in the matchstick puzzle below?