Why 1729 is a magic number? Answer Logically.

Christina is practising her dance steps along with her friends. In a particular sequence, all of them form a row. At that point, Niharika is standing in the 4th position from either end of the row.
Can you find out how many girls are practising together?

What number comes next in this sequence:
7 8 5 5 3 4 4 _

An inspection by the superintendent of St. Joseph School was scheduled on the next day. The class teacher Jenifer knew that he would be asking questions from her class and she would have to choose a pupil to answer. To offer a perfect impression over him, the teacher explained certain instructions to the students to maximise the chances of getting correct answer every time.

What did she say to the students?

Until it is measured, not known. Yet how you miss it when it has gone. What is it?

A word I know has six letters it contains, remove one letter and 12 remain. What is it?

Christina, Allison and Lena are 3 daughters of John a well-known Mathematician, When I asked John the age of their daughters. He replied "The current age of her daughters is prime. Also, the difference between their ages is also prime."

How old are the daughters?

When monkey rotate the gear, which mark will be hit 1 or 2 ?

I am the fastest animal but cannot climb the tree. What am I?

Replace the 'X' with any mathematical symbol to make the expression equal to 111.

18 X 12 X 2 X 3 = 111