Can you place six X (crosses) in below board without making three in a row in any way ?

I know a nine-letter word having only one vowel.
Do you ?

Decode the below four famous ciphers:

8P of the SS
1M of the E
1S of the SS
60M in 1H

Pronounced as one letter,
And written with three,
Two letters there are,
And two only in me.
I am double, I am single,
I am black blue and grey,
I am read from both ends,
And the same either way.

What mathematical symbol can be put between 5 and 9, to get a number bigger than 5 and smaller than 9?

Here is what you have to do. You have to throw a ball as hard as you can but it must return back to you even if it does not bounce at anything. Also, you have nothing attached to the ball. There is no one on the other end to catch that ball and throw it back at you.

How will you do it?

What are the 50th, 63rd and 100th numbers in the sequence below?
4, 5, 8, 8, 9, 9, 12, 13, 13, 13, 17, 18, ...

If you go to the movies and you're paying, is it cheaper to take one friend to the movies twice, or two friends to the movies at the same time?

Always in you, Sometimes on you;

If I surround you, I can kill you.

What am I?

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?