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

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?

There are nine letters in the below-given diagram. You have to form a nine-letter word using these letters.

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 inserted a coin in a bottle and closed its mouth with the help of a cork. Now, I was able to take the coin out from the bottle without taking out the cork or breaking the bottle. Can you tell me how I did it?

I am the beginning of the end, and the end of time and space. I am essential to creation, and I surround every place. What am I?

You walk into a room that contains a match, a kerosene lamp, a candle and a fireplace. What would you light first?

You walk into a room that contains a match, a kerosene lamp, a candle and a fireplace. What would you light first?

Solve the following series:
AZ, GT, MN, __, YB

Considering the below equation:

V + II - VI = 10
IV - X + VIII = 20
IV - VII + VI = 30

Then, I + II + III = ?