# Problem of logic

japy104
Posers and Puzzles 15 Feb '10 16:05
1. 15 Feb '10 16:05
A postman rings at a door. A man opens the dorr and tells the postman :

"Hi, I have 3 daughters. Multiplying their ages gives 36, and adding their ages is the number of the white house behind you."

The postman looks at the house and says : "I don't see !"

The man replies : "Oh, I forgot telling you : the eldest one is blond !"
and the postman gives the three ages (in full years, idest 7, 13, ..).

What are the three ages ?
2. wolfgang59
15 Feb '10 18:49
Originally posted by japy104
A postman rings at a door. A man opens the dorr and tells the postman :

"Hi, I have 3 daughters. Multiplying their ages gives 36, and adding their ages is the number of the white house behind you."

The postman looks at the house and says : "I don't see !"

The man replies : "Oh, I forgot telling you : the eldest one is blond !"
and the postman gives the three ages (in full years, idest 7, 13, ..).

What are the three ages ?
I think I've got it!
3. joe shmo
Strange Egg
16 Feb '10 05:261 edit
Originally posted by japy104
A postman rings at a door. A man opens the dorr and tells the postman :

"Hi, I have 3 daughters. Multiplying their ages gives 36, and adding their ages is the number of the white house behind you."

The postman looks at the house and says : "I don't see !"

The man replies : "Oh, I forgot telling you : the eldest one is blond !"
and the postman gives the three ages (in full years, idest 7, 13, ..).

What are the three ages ?
Im going to take a shot and say 9,2,2.....

I started by listing all factors of 36

36,18,12,9,6,4,3,2,1

since 36 is not a perfect cube rule out triplets

I come up with 7 possibilties in no particular order for 3 factors of 36 multiplied to give 36

9*4*1, 6*6*1 ,36*1*1 ,18*2*1 ,6*3*2 ,9*2*2 ,3*3*4

which have coresponding sums

14, 13,38,37,11,13,10

Since the postman doesnt see the numbers on the white house the sum is irrelivant

narrowing it down to possibilities with equal sums

6*6*1 and 9*2*2

only one of which has an eldest

9,2,2
4. 16 Feb '10 08:08
You are right. With any other number on the house, the postman could have said the ages. Good. In fact, I saw the same puzzle posted months before in this list.
5. wolfgang59
16 Feb '10 08:45
Originally posted by joe shmo
Im going to take a shot and say 9,2,2.....

I started by listing all factors of 36

36,18,12,9,6,4,3,2,1

since 36 is not a perfect cube rule out triplets

I come up with 7 possibilties in no particular order for 3 factors of 36 multiplied to give 36

9*4*1, 6*6*1 ,36*1*1 ,18*2*1 ,6*3*2 ,9*2*2 ,3*3*4

which have coresponding sums

14, 13,38,37 ...[text shortened]... to possibilities with equal sums

6*6*1 and 9*2*2

only one of which has an eldest

9,2,2
I figured if the children were 9,2,2 it would be obvious who was the eldest and that the man said his eldest was blonde to distinguish her from her brunette twin; hence 6, 6, 1

Didnt twig that 13 was the only duplicate sum ... reasoned that the owner of the White House was superstitious therefore no number implied 13!
6. 23 Mar '10 16:28
Originally posted by joe shmo
narrowing it down to possibilities with equal sums
6*6*1 and 9*2*2
only one of which has an eldest
9,2,2

Actually 6,6,1 is also correct.
One of the twins have to be the oldest, you know ðŸ˜€
And the oldest can be blond, just as the other twin.
7. 23 Mar '10 19:35
Originally posted by tolder
Presumably they are non-identical twins otherwise the statement would be unhelpful.