Many have heard it, but nobody has ever seen it, and it will not speak back until spoken to. What is it?

How old is your son? asked a man to his neighbour. My son is five times as old as my daughter and my wife is five times as old as my son. I am twice as old as my wife whereas my grandmother, who is celebrating her eighty-first birthday is as old as all of us put together.

How old is the man's son ?

Can you name an animal whose killing cannot be performed without spilling your own blood?

A thief is convicted in Mexico. He gets the death penalty. The judge allows him to say the last sentence to determine how the penalty will be carried out. If the thief lies, he will be hanged, if he speaks the truth he will be beheaded. The thief tells the last sentence and to everybody's surprise some minutes later he is set free because the judge cannot determine his penalty. What did the thief say?

A sundial has the fewest moving parts of any timepiece. Which has the most?

There was a blind man. He had four socks in his drawer either black or white. He opened it and took out two socks. Now the probability that it was a pair of white socks is 1/2.

Can you find out the probability that he had taken out a pair of black socks ?

Can you find the missing letter in the sequence?
S - T - I - L - ? - T - F - Y - C

With the help clues provided in the image, can you find the 5 digit key?

Luis Garavito killed Density x Volume.

Who is Luis Garavito ?

Which English verb becomes past tense just by rearranging the letters?