What number should come in place of the question mark below?

You can see it everyday, But cannot touch it at will. What is it?

You need to pick one entry from pot A and one from pot B to have a perfect match. Can you do it?

If,
29 - 1 = 30
9 - 1 = 10
14 - 1 = 15

Based on similar logic, Can you prove that the below algebraic equation is true?
11 - 1 = 10 ?

Christina has four daughters, and each of her daughters has a brother. How many children does Christina have?

Count The number of F's in the paragraph below:

"FINISHED FILES ARE THE RESULT OF YEARS OF SCIENTIFIC STUDY COMBINED WITH THE EXPERIENCE OF YEARS"

I always drive my customer away.

Who am I?

John was drowned by he was not wet. How?

A man died and leaves Rs.10,000 in his will. There are 6 beneficiaries- his 3 sons and their wives. The 3 wives receive Rs.3960 of which Priyanka gets Rs.100 more than Tanu and Neha gets Rs.100 more than Priyanka.
Pramod gets twice as much as his wife, Tushar gets the same as his wife, and Prashant gets 50% more than his wife.

Who is married to whom?

I make two people out of one. What am I?