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

The square root of number 121 is "11". What is the square root of the number "12345678987654321."?

How can one talk without saying a single word?

There are nine letters in the below-given diagram. You have to form a nine-letter word using these letters.

I am a prime number.
The double of myself is equal to the square of me.

which number am I?

You walk into a room that contains a match, a kerosene lamp, a candle and a fireplace. What would you light first?

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?

How is a fly different from a mosquito?

I have holes on the top and bottom. I have holes on my left and on my right. And I have holes in the middle, yet I still hold water. What am I?

All of the flowers I have are orchids except two. All of the flowers I have are hibiscuses except two. All of the flowers I have are roses except two.

Can you tell me how many flowers I have?