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

which number am I?

What begins with T, ends with T, and has T in it?

Can you find out the total number of triangles in the given figure?

Name a key which is hardest to turn.

I know a ten-letter word in the English language which can be typed using only the top rows of the computer keyboard.

What is the difference between a jeweller and a jailer?

If you were to put a coin into an empty bottle and then insert a cork into the neck, how could you remove the coin without taking out the cork or breaking the bottle?

Which word is least like the others? Third, fourth, fifth, sixth, seventh, eighth, ninth?

There was once a college that offered a class on probability applied to the real world. The class was relatively easy, but there was a catch. There were no homework assignments or tests, but there was a final exam that would have only one question on it. When everyone received the test paper it was a blank sheet of paper with a solitary question on it: 'What is the risk?'.Most students were able to pass, but only one student received 100% for the class! Even stranger was that he only wrote down one word!
What did he write?

Count the number of triangles in the given picture.