wu :: forums « wu :: forums - daughter's ages » Welcome, Guest. Please Login or Register. Sep 21st, 2018, 8:40pm RIDDLES SITE WRITE MATH! Home Help Search Members Login Register
 wu :: forums    riddles    hard (Moderators: william wu, towr, Icarus, Grimbal, Eigenray, SMQ, ThudnBlunder)    daughter's ages « Previous topic | Next topic »
 Pages: 1 Reply Notify of replies Send Topic Print
 Author Topic: daughter's ages  (Read 2969 times)
klbarrus
Newbie

Posts: 29
 daughter's ages   « on: Jul 25th, 2002, 5:03pm » Quote Modify

The product of Dr. D's daughter's ages is 72, or 3*3*2*2*2. Trying out various combinations, we get these possibilities:

18, 2, 2; sum 22
9, 4, 2; sum 15
12, 3, 2; sum 17
6, 6, 2; sum 14
8, 3, 3; sum 14
6, 4, 3; sum 13

Since Dr. S can't figure out the ages from their sum, it must be either 6, 6, 2 or 8, 3, 3 as they both add to 14, and the rest are unique.  Dr. D said "his oldest" so this means his daughters are 8, 3, 3.

Of course, Dr. D might have been talking about the oldest twin of the 6 year old pair
 IP Logged
Zy Baxos
Guest

 Re: daughter's ages   « Reply #1 on: Jul 26th, 2002, 8:53pm » Quote Modify Remove

You are ignoring a large number of possible age combo's:

1,1,72 - all right, not *that* possible
1,2,36 - "
1,3,24
1,4,18
1,6,12
1,8,9

Fortunately, all of these combinations have unique sums, so your answer still holds

Regards,
Zy
 IP Logged
klbarrus
Newbie

Posts: 29
 Re: daughter's ages   « Reply #2 on: Jul 27th, 2002, 11:33pm » Quote Modify

Doh!  Thanks, I skipped all the factors of 1 as you said.
 IP Logged
 Pages: 1 Reply Notify of replies Send Topic Print

 Forum Jump: ----------------------------- riddles -----------------------------  - easy   - medium => hard   - what am i   - what happened   - microsoft   - cs   - putnam exam (pure math)   - suggestions, help, and FAQ   - general problem-solving / chatting / whatever ----------------------------- general -----------------------------  - guestbook   - truth   - complex analysis   - wanted   - psychology   - chinese « Previous topic | Next topic »