Can you replace the question mark with the correct number?

A blonde put eyeliner on her head. Why?

Christina is older than Kareena and Karishma. Katrina is older than Karishma and younger than Kareena. If Kareena has a brother named John, who is older than Christina, who's the youngest?

John was a very careless driver, so his owner Jacob gave him an offer that he will get an incentive of Rs.30 for every bottle box he delivered without breaking it and he will be charged Rs.90 for every bottle box he broke. Jacob gave John 100 bottles-box to deliver. After delivery, Jacob paid John Rs.2400. How many bottles-box did John break?

Most people think of me as money. But when they find me in the water, they won’t get any money out of me. What am I?

In the attached figure, you can see a chessboard and two rooks placed on the chess board. What you have to find is the number of squares that do not contain the rooks. How many are there?

I am beautiful, up in the sky. I am magical, yet I cannot fly. To people I bring luck, and to some people, riches. The boy at my end does whatever he wishes. What am I?

Can you solve this amazing hard number series problem?
7, 8, 10, 12, 16, 18 ?

It comprises roots which nobody sees,
Much taller than those trees,
Up and up it goes,
Still it never grows?

The Little ant seems to be always confused. Do you know why?