Don't google this one. It's tricksy.
One day walking in a street, Caesar meets his old math teacher. Happy to meet him, he says hello to the teacher but he doesn't remember that his teacher answers everything with a puzzle:
-- How are you doing, professor? It's been a long time since we don't meet! Are your daughters ok? How old are they now?
-- Multiplying the three ages you get 36
-- But that's not enough to know the ages!
-- So, add up the ages and you'll get the number of that house across the street.
Caesar starts calculating, but still can't figure out. The professor seeing that he wouldn't be able to find the answer says:
-- The oldest girl plays the piano...
That's what Caesar needed to know to figure out the problem. How old is each girl?