Since the product was expressed as an integer by the person answering the door, and house and apartment numbers tend to be integers, and everyone except small children express their ages as a year in an integer that it one of the twins didn't answer the door.

>Not true at all. one of the two 15 year olds is older than the other if only by a second. Every twin I've ever asked the question one of them is quite proud to be the older of the two.
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>>3,3,25 is the answer because the cenus taker knows the house number, but because he has to ask an extra question to determine the ages, that must mean that the house number must be a set of ages with the same sum. That being 3,3,25 and 1,15,15. Since the person that answered the door is the oldest (and not tied for the oldest) the answer has to be 3,3,25.