What is both possible and impossible at the same time?

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

Can you calculate the probability of getting a sum of six when a dice is thrown twice?

Two girls were born to the same mother, on the same day, at the same time, in the same month and year and yet they're not twins. How can this be ?

I am a seven-letter word but if you remove four of my letters I will have one left. What word am I?

Who has married many women but was never married?

He runs but never walks. Murmurs, but never talks. Has a bed, but never sleeps. And has a mouth, but never eats?

John is found dead in a bare field. Nobody killed John,
John did not commit suicide.

Inspector Jacob found a bag just a few meters away from John which could save his life. What was in the bag?

I am a white box having no key or lid.
Yet there is a golden treasure inside it.

What Am I?

A Monkey, a squirrel, and an Eagle are racing to the top of the mango tree. Assuming all these animals are in perfect shape, Which animal will reach to Banana first?