A difficult question on sets.
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# A difficult question on sets.

[From: ] [author: ] [Date: 11-05-20] [Hit: ]
Find n.Since Im not quite sure I got the question right I wish to first ask if anybody else remembers seeingthis question (maybe I dreamed it...) or if it is familiar from other sources.If so,......
This question appeared here last week (and was titled :"Set theory help") but was deleted before I managed to verify the details.
The question was also not written very clearly.
AsI I recall the question, it was as follows:
"A union of 30 sets named Ai i=1 to 30 where each Ai has exactly 5 elements is equal to a union of n sets Bi i=1 to n where each Bi has 3 elements.
Call this union S.
It is known that each element of S belongs to exacly 10 sets of Ai's and exactly 9 sets of Bi's.
Find n."

Since I'm not quite sure I got the question right I wish to first ask if anybody else remembers seeing this question (maybe I dreamed it...) or if it is familiar from other sources.
If so, is there any further information I have omitted?
Secondly, I would of ,course like to know if the question is solvable since at first glance it doesn't seem to me that n is uniquely determined by the given information.
Finally, just out of curiosity (this is partly aimed at "Yahoo Answers" administrators), can anyone explain what "community guidelines" were violated by this question?

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I didn't see that one. However, as you've written it, the answer would be given by
30 * 5 / 10 = n * 3 / 9

n = 45

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As for your last question... AFAIK, the message given for a deleted question is the same, whether it's reported and removed for a violation, or deleted by the person who posted it.

I would expect it was deleted by the person who asked it.
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