The other day, Jim excitedly told me, "Did you realise I will turn x years old in the year x^2?"

He wasn't the first to think of this. The 19th century mathematician August de Morgan used to used to boast that he was x years old in the year x^2. He died in 1871.

In what year was Jim born? When will his prediction be true? In what year was de Morgan born? What is x in each case?

The problem itself isn't much to get your mind around, just find a year that is a perfect square and subtract its square root.

Ravi, you're just being argumentative for the sake of arguing. The problem on my screen says "Posted on 2003-04-15" and begins with the words "the other day," and Jim is talking entirely in present tense, as is the question posed at the end of the problem. Supposing this puzzle is from before 1936, and for some reason was preserved verbatim until today, I think it probably would have been made clear in the problem, but sure, Jim could have been turning 44. If the puzzle is from between 1936 and 1980, you can't say that either answer is valid; rather, both answers are invalid because either Jim has already turned 44, or he hasn't been born yet. So either the problem is more than 67 years old, or it is relatively recent and is worded accordingly. To me, there shouldn't be much of a pressing debate here...

Posted by DJ on 2003-04-20 14:34:57