Replace the question mark with the correct number in the below-given picture?

Is the statement valid that it does not matter how much older a sibling is, eventually the younger one will be half as old as the older one?

What is the Surname of Barbie Doll?

A boy and his father are caught in a traffic accident, and the father dies. Immediately the boy is rushed to a hospital, suffering from injuries. But the attending surgeon at the hospital, upon seeing the boy, says 'I cannot operate. This boy is my son.' How is this situation explained?

Find the hidden tiger in the given optical illusion ?

If you say my name, I will no longer exist. What am I?

You need to arrange three 7 and mathematical symbols to form number 1?

Two-person want to cross a river. Only one boat is present on the riverside that can carry only one person at a time.

However, they still manage to cross the river. How is it possible?

Buy me, smell me or deliver me, I do not change.

Who am I?

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