Puzzle - Rate
My grandfather was X years old in the year X squared. In which year was he born?
For example if he was 33 years old in the year 1089 AD (= 33 x 33), he would have been born in 1056 AD - but then of course he would currently be nearly a thousand years old! You can safely assume that none of my family had children when they were very, very old, and I'm not too old myself.