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

In which direction should the missing arrow point?

Which is the smallest number that you can write using all the vowels exactly once?

Why do we preferably have round manhole covers and not square ones?

Many have heard it, but nobody has ever seen it, and it will not speak back until spoken to. What is it?

You visit a home for specially-abled children on the occasion of Christmas where you meet with 50 children. You have a box of chocolates containing 50 chocolates exactly.

What if you were asked to one chocolate to each child in a manner that one chocolate still remains in the box? Is it possible?

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?

There is a square of a particular number which when doubled, becomes 7 more than its quarter.

Can you find the number?

Always in you, Sometimes on you;

If I surround you, I can kill you.

What am I?

Mr Black, Mr Gray, and Mr White are fighting in a truel. They each get a gun and take turns shooting at each other until only one person is left. Mr Black, who hits his shot 1/3 of the time, gets to shoot first. Mr Gray, who hits his shot 2/3 of the time, gets to shoot next, assuming he is still alive. Mr White, who hits his shot all the time, shoots next, assuming he is also alive. The cycle repeats. If you are Mr Black, where should you shoot first for the highest chance of survival?