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

Transform the word THINK into BRAIN while changing only one letter at a time in a manner that each of the word in the process is a real word!!!

I have no doors but I have keys, I have no rooms but I have space, you can enter but you can’t leave! What am I?

I have an eye but still cannot see.

Who am I?

100 prisoners are stuck in the prison in solitary cells. The warden of the prison got bored one day and offered them a challenge. He will put one prisoner per day, selected at random (a prisoner can be selected more than once), into a special room with a light bulb and a switch which controls the bulb. No other prisoners can see or control the light bulb. The prisoner in the special room can either turn on the bulb, turn off the bulb or do nothing. On any day, the prisoners can stop this process and say "Every prisoner has been in the special room at least once". If that happens to be true, all the prisoners will be set free. If it is false, then all the prisoners will be executed. The prisoners are given some time to discuss and figure out a solution. How do they ensure they all go free?

Can you find out which options fits best with the missing column?

Cristina leaves home and then she makes exactly 3 left turns and returns home where she found 2 girls wearing the mask.

Who are these two masked girls?

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

Eight of us go fourth, not back, to protect our king from an attack. What are we?

Can you place three balls such that the equation shown in the picture holds true?