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

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

Find The Next Number in this series.
1, 2, 6, 42, 1806 ?

What can you hold in your right hand, but never in your left hand?

I get hot but I never sweat,
I cook food but I am not a chef,
I have a door but you can't enter me,
I have a light but I am not a lamp.
Who am I?

I am quite hot but become too cold if you remove the first two letters. What am I?

There is an English word that can be used up to four times in a row without modifying the spelling and form a valid grammatical sentence.

Do you know what word is that?

A newspaper is supposed to have 60 pages, but pages 24 and 41 are missing.
Which other pages won't be there?

A horse was tied to a rope 5 meters long and the horses food was 15 meters away from the horse. How did the horse reach the food?

A Scientist was fifty years old in the year 2000 but he was forty years old in the year 2010. How can this be possible?

PS: It has a logical answer.