The Old Ship

          Some years back I was travelling by a cargo ship from New Zealand to Tahiti. I was curious to look around the ship one day, and in the boiler room I asked a man how old the ship was. He smiled and replied in this way: The ship is twice as its boiler was when the ship was as old as the boiler is now. And the combined age of the ship and the boiler is thirty years.’

       Can you figure out what is the age of the ship and of the boiler?

Answer: Let’s assume that the age of the ship at present is X years and of the boiler Y years.

Then

The ship X is twice as old as its boiler (Y-X) was when the ship was (x-X) as old as the boiler is now.

X= 2 (Y-X) and (x-X) = 2 

Eliminating X gives 4Y = 3X            Also, x+Y = 30

Y (the boiler) = 90/7   years. And X (the ship)

=120 years.