This puzzle appeared in the April 1960 issue of Popular Science.

(Click on thumbnail for enlargement)

Answer will be posted on Saturday.

Via Boing Boing

[UPDATE: Here's the answer: The ages of the three people are 25,3, and 3. Anyone know how that's derived? I'll post that tomorrow.]

[UPDATE #2: Here's the logic behind the answer:

There are 8 sets of possible ages (derived from factoring 225), shown below with their sum in parentheses:

225, 1, 1 (227)
9, 5, 5 (19)
75, 3, 1 (79)
25, 9, 1 (35)
45, 5, 1 (51)
15, 5, 3 (23)
25, 3, 3 (31)
15, 15, 1 (31)

The census guy knows the house number, but he needs to ask another question. This must be because he doesn’t have enough info from the house number and the fact that the product of the ages is 225. This must mean that the ages sum to 31, since there are 2 sets of ages that could sum to 31: 25+3+3 and 15+15+1. By asking if the person answering the door is the oldest he can elimiate 15+15+1 where there is no unique oldest person.]