What Ages Solve the Postmen's Riddle?

  • Context: High School 
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Discussion Overview

The discussion revolves around a riddle involving the ages of three sons of a postman, where the ages are related through multiplication and addition to the postman's age and the number of windows in a building. Participants explore the implications of the clues provided, particularly focusing on the significance of the middle child's age and the red-haired characteristic.

Discussion Character

  • Exploratory
  • Debate/contested
  • Mathematical reasoning

Main Points Raised

  • Some participants suggest that the postman's age is necessary to solve the riddle, as it provides a numerical constraint.
  • Others argue that the clue about the middle son being red-haired is sufficient to deduce the ages of the children.
  • One participant notes that the ages must be distinct, implying that no two sons can be the same age.
  • Another participant discusses the mathematical implications of the ages being derived from prime factorization and the conditions that arise from the clues given.
  • Some participants express skepticism about the reasoning provided by others, questioning the validity of certain conclusions drawn from the clues.
  • There is a discussion about the significance of the middle child in resolving ambiguities in the possible ages of the sons.

Areas of Agreement / Disagreement

Participants do not reach a consensus on whether additional information is required to solve the riddle. Some believe the clues provided are sufficient, while others maintain that the postman's age is essential for a definitive solution. The discussion remains unresolved regarding the implications of the clues and the correct ages of the sons.

Contextual Notes

Participants highlight the ambiguity surrounding the number of windows in the building and the lack of specific numerical values, which complicates the problem. The discussion also touches on the assumptions made about the ages and the nature of the clues provided.

  • #31
Be happy it wasn't "My youngest son has red hair"

Then the choices would be:
36:
2,2,9
1,6,6

40:
2,2,10
1,5,8

or

90:
3,3,10
2,5,9
 
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  • #32
why couldn't you have 2 children of the same age who weren't twins? they could b 3, 3, 10 with one of the 3 year olds being older than the other. even if they are twins, one of them would still be older, and therefore the middle child.
 
  • #33
Unless the postman worked in Utah, this would be highly unlikely. I'll let the biology folks tell us the least time between successive births (I know there are several factors involved, including how long you breast-feed)...but I'm sure that 2 births from one woman, less than a year apart is virtually unheard of.

Or he could always divorce a pregnant wife; re-marry and make his new wife pregnant in short order...

Or there could be illegitimate children...

Clearly, we're nitpicking and getting beyond the intended realm of the puzzle.
 
  • #34
You really tripped them up with this one.
 
  • #35
I don't know how rare it is, but I'm 10 months older than my younger brother.
 
  • #36
Brennen said:
why couldn't you have 2 children of the same age who weren't twins? they could b 3, 3, 10 with one of the 3 year olds being older than the other. even if they are twins, one of them would still be older, and therefore the middle child.

Well, while you're at it, why don't we allow non-integer ages. That way there's an infinite number of possible combinations.

In practice, there is almost always an older twin and a younger twin, since they don't come out at the same time, but a few minutes apart.
 
  • #37
I grew up with 2 kids that are 11 1/2 months apart.
 
Last edited:
  • #38
not to mention that a 90 year old man probably wouldn't have kids that younge.
Great problem though
 
  • #39
NateTG said:
Be happy it wasn't "My youngest son has red hair"

Then the choices would be:
36:
2,2,9
1,6,6

40:
2,2,10
1,5,8

or

90:
3,3,10
2,5,9

Speaking of a postman who's 36, is it not also possible that the children are 1, 3, and 9? This still satisfies all the requirements of the original problem, it seems to me.
 
  • #40
Adelaine said:
Speaking of a postman who's 36, is it not also possible that the children are 1, 3, and 9?
1*3*9=27 :biggrin:
 
  • #41
For anyone interested, I ran a script on all the possible solutions for this problem assuming that:

1) the product is <= 1000
2) the numbers ("ages" in this case) are positive, whole numbers

Solutions assuming there's a "middle child":
1,5,8
2,5,9
3,6,8
1,13,18
1,12,21
1,11,27
2,10,16
5,8,9
2,9,24
3,10,15
1,10,45
3,8,27
3,9,25
6,8,15
4,10,18
1,25,32
1,24,34
2,17,25
1,22,40
5,9,20
2,9,50

If the problem specified "youngest child", you would get:
1,6,6
1,5,8
2,6,6
2,5,9
3,6,8
1,15,15
1,13,18
1,12,21
2,12,12
1,11,27
2,10,16
5,8,9
2,9,24
3,10,15
1,10,45
4,12,12
3,9,25
4,10,18
1,28,28
2,20,20
1,25,32
1,24,34
2,17,25
1,22,40
3,18,18

"Oldest child":
2,2,9
3,3,8
3,3,25
4,4,18
6,6,16
3,8,27
6,8,15
4,4,49
5,5,32
5,9,20
2,9,50
6,6,27

DaveE
 
  • #42
Evo said:
If you really wanted to be fussy, since a house cannot have a fraction of a window, it also means that the ages of the sons must all be in integers (whole numbers) and not involve fractional ages.

What if more than one of them has a fractional age?

This part is just stupid
 

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