Age problem from Mathematical Conundrums

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    Age Algebra Puzzle
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38 replies · 9K views
pinball1970 said:
I missed a Teams because of this.
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pinball1970 said:
Not to me and @Curious Kev was on the site less that three hours regarding this question. That's bad form on pf Kev.
Yeah, "curious" kev wasn't very curious after all.
 
pinball1970 said:
What does 27 mean?
27 in the post #24 is the result of my misinterpretation of the problem statement and you can skip it.

pinball1970 said:
I think I don't like the word "ago."
Should it be "before?"
“ago” is correct in this case. See the original post.
 
phinds said:
Yeah, "curious" kev wasn't very curious after all.
It is better to assume ignorance before malevolence. Please remember, I am a real human being. You must imagine that you are talking to me in a room and that you can see my facial reaction to your comment. From what I've read, Gavran and PeroK have been very helpful. Thanks.
 
I think there is a bit more to explore to this problem. For example, what is the current relationship between the ages of Holly and Ivy? What can we say about who is older or younger? Also, what constraints can we place on the minimum ages if we demand both were alive at the different times mentioned in the problem?
 
We don’t have enough information to calculate the ages of Holly and Ivy but we can determine the relationship between them. Using the original conditions which we calculated at 6 years ago, we can say that ##H=2I-24## so Holly’s age is always twice that of Ivy minus 24 years. ##H## and ##I## refer to their current ages. Note that if Ivy is older than 24, Holly is older and if Ivy is younger than 24 Holly is younger. If Ivy is exactly 24 then so is Holly (they could be twins).
 
Also, the minimum age for Ivy such that Holly is alive 15 years ago is 19.5 years old.
 
bob012345 said:
Also, the minimum age for Ivy such that Holly is alive 15 years ago is 19.5 years old.
The question does not imply that Holly was alive 15 years ago. It does imply that Ivy was alive 15 years ago, and so Ivy's minimum age is 15 (or 16 if you do not consider 0 to be a valid age).

However this is irrelevant to the answer to the question which is indeed 6.
 
It is an unusual problem in that two of the three unknowns are dependent on one another so there are really only two unknowns. I suppose that's the point.