Which word does the below Plexor means ?

If eleven plus two equals one, what does nine plus five equal?

A large container is kept in open under the rain. Every passing hour, the water collected inside the container becomes double what it was.

In ten hours, the container is filled completely. Can you calculate how long would it have taken to be filled in half?

If 21x = 79x, what is the value of x?

Solve below popular number sequence
314 159 265 358 979 323 846 ?

John killed hundreds of people mercilessly and yet the police were not able to put her behind the bars. Why?

If,

A = 1

B = 2

C = 3

...

...

Z = 26.

Based on above rule, you need to find an eleven letter word whose letter sum is equal to 52.

Move three sticks of the spiral below to form a square.

Two guards were on duty outside a barracks. One faced up the road to watch for anyone approaching from the North. The other looked down the road to see if anyone approached from the South. Suddenly one of them said to the other, "Why are you smiling?"

How did he know his companion was smiling?

I start and end with 500 and carry a 5 in my heart. But I require the first letter and the first number to be complete. I am the name of a King.

Who am I ?