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?
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?

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

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.
30 * 5 / 10 = n * 3 / 9
n = 45

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.