Which of the below owl is odd one out?

Solve the below puzzle by replacing the question mark with the correct number.

3 6 12

4 8 16

5 10 ?

What's the only room from which no one can enter or leave

As easy as you can get into me, it is as hard to get out of me.

Do you know what I am?

When I get multiplied by any number, the sum of the figures in the product is always me. What am I?

O_er_t_o_

Complete the missing letters of the given word.

using four eights (8) and a one (1) and one mathematical symbol , create the number 100

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?

Can you name four days which start with the letter 'T'?

Consider all the numbers between 1 and 1 million. Among all these numbers, there is something very special about the number 8 and the number 2202. What is it?