Ok so say the cardinality of.....

$\displaystyle U=120 ,A=58, B=40, C=46 AB=13,AC=11,BC=17$

How do I find |ABC|

note:all adjacent sets are intersect. This completely vexes me.

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- Nov 26th 2011, 12:31 PMehpocMore set theory trouble
Ok so say the cardinality of.....

$\displaystyle U=120 ,A=58, B=40, C=46 AB=13,AC=11,BC=17$

How do I find |ABC|

note:all adjacent sets are intersect. This completely vexes me. - Nov 26th 2011, 12:51 PMPlatoRe: More set theory trouble
- Nov 26th 2011, 01:18 PMehpocRe: More set theory trouble
I honestly do not understand how we can come to any single conclusion about |ABC|

- Nov 26th 2011, 01:23 PMPlatoRe: More set theory trouble
- Nov 26th 2011, 01:29 PMAlso sprach ZarathustraRe: More set theory trouble
- Nov 26th 2011, 01:30 PMehpocRe: More set theory trouble
So when a question ask "What is |ABC|" it is not really asking that? Why would the question not ask what is the maximum that |ABC| could be?

So when you say 11 you are saying "there is at most 11 elements in ABC"?

Oh btw I just realized that I missed out one key premise.... AuBuC=109 I think I can solve it now. I keep getting psyched out by these problems and choking really.

EDIT: nope still can't solve it. LOL - Nov 26th 2011, 01:50 PMPlatoRe: More set theory trouble
- Nov 26th 2011, 09:48 PMAnnatalaRe: More set theory trouble
If you're having trouble visualizing this, a Venn Diagram is just what the doctor ordered. (Particularly with three sets, where all intersections are represented.)