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        riddles >> hard >> Daughters' Ages
        
(Message started by: hakejam on Nov 3^rd, 2003, 12:57pm)

Title: Daughters' Ages
Post by hakejam on Nov 3^rd, 2003, 12:57pm

First of all, long time lurker, first time poster! Finally got up the nerve to post.

My first impression was that this problem isn't very hard. Here is what I did:

[hide]
Since Dr. Demmel said that the product of his three children is 72, I found the prime factors of 72:

2x2x2x2x3x3

So his children has the possiblity of being a compantion of those:

4, 3, 6
8, 3, 3
12, 2, 3
9, 4, 2
6, 6, 2
18, 2, 2
9, 8, 1

He then goes on to say that the sum of them is the same of the number on a building on Telegraph Avenue.

I searched the Berkeley site for places on Telegraph Avenue. I couldn't find any numbers with the sum of any of the numbers that I got.

The riddle goes on to say that the oldest just started to learn the piano. Couldn't find any significance in this sentence.

My best guess would be that his daughters are 9, 4, 2 or 9, 8, 1.

What am I missing?
[/hide]

Title: Re: Daughters' Ages
Post by towr on Nov 3^rd, 2003, 1:35pm

You are missing that "Telegraph Avenue" clue wasn't enough to determine the answer ([hide]which means all unique sums are ruled out[/hide]). And that the 'oldest one' clue was sufficient to find the definite answer, using the information up to that point.

You might also have missed the search option (http://www.ocf.berkeley.edu/~wwu/cgi-bin/yabb/YaBB.cgi?board=riddles_hard;action=search) at the top of the forum, but since it doesn't seem to be working for me (either) at the moment, that's a mute point :P

Title: Re: Daughters' Ages
Post by Icarus on Nov 3^rd, 2003, 3:34pm

Since towr is unable to provide, here is a link to one of the earlier threads (http://www.ocf.berkeley.edu/~wwu/cgi-bin/yabb/YaBB.cgi?board=riddles_hard;action=display;num=1027806330) on this puzzle.

Very seldom do any of these riddles require "local" knowledge, even when they seem to. There are some exceptions, but those are member posts, not William's official puzzles (of course he apparently has given up on updating the puzzle pages, since he is posting all his puzzles on the forum these days as well!)

But anyway, hakejam, we're glad to hear from you!

Title: Re: Daughters' Ages
Post by SL on Jan 22^nd, 2004, 5:10pm

There are actually more options than those 7 listed by hakejam.
Also the 6,6,2 can't work since one girl is the oldest.
There can be:
6,4,3
8,3,3
12,2,3
9,4,2
18,2,2
9,8,1
36,2,1
72,1,1
24,3,1
18,4,1
12,6,1

Title: Re: Daughters' Ages
Post by casual_kumar on Aug 11^th, 2006, 6:22am

I was surprised to see this puzzle with incomplete answer, well I am trying
6,4,3 sum = 13
8,3,3 sum = 14
12,2,3 sum 17
9,4,2 sum = 15
18,2,2 sum = 22
9,8,1 sum = 18
36,2,1 sum = 39
72,1,1 sum = 74
24,3,1 sum = 28
18,4,1 sum = 23
12,6,1 sum = 19
6,6,2 sum = 14

So, now the information is enough to solve the puzzle. Forget the house number, we don't need it. But the fact that even the sum and product can't give a unique solution is a superb hint. See above, whats the house no. that still does not identify a unique set of factors? Its 14 so the house no. is clearly 14 as any other house number would have identified a set and there was no need for another hint. Also, as the oldest one is playing the piano so she is a unique person, among (8, 3, 3) and (6, 6, 2) the former has a unique elder sister!!!

theres your solution...

Title: Re: Daughters' Ages
Post by casual_kumar on Aug 11^th, 2006, 6:26am

hey thats not fare, i just checked the other thread and the solution lies there. Now I don't feel like having solved the puzzle. >:(

Title: Re: Daughters' Ages
Post by BNC on Aug 11^th, 2006, 7:29am

on 08/11/06 at 06:26:45, casual_kumar wrote:

hey thats not fare, i just checked the other thread and the solution lies there. Now I don't feel like having solved the puzzle. >:(

casual_kumar,

Just because someone sloved a puzzle before you did, should not take away your feeling of success. This forum has been going on for some years now, so there are probably thousands of solved riddles here. This is, BTW, the reason you'll notice many of us giving hints rather than posting the solution -- to allow others the joy of puzzling. You'll notince also we don't keep 'score' of solved problems. Solving the problem by yourself is a reward by itself!

Title: Re: Daughters' Ages
Post by casual_kumar on Aug 12^th, 2006, 12:14am

Thanks for the supportive post. I am really enjoying this forum.