Thread: Probability help please

Hey guys, I need some help on this problem please

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Verify the following extension of the addition rule by a) an appropriate Venn diagram and b) by a formal argument using the axioms of probability and the propositions in the chapter.




I don't understand the last part which says: because they are now adding some of the same elements twice. But the question does say VERIFY and not prove...

Thanks in advance.

is the intersection between the three sets A, B and C

The following Venn diagram may be of help:

Originally Posted by colby2152

is the intersection between the three sets A, B and C

The following Venn diagram may be of help:

Ah i get it now! After we removed the intersections of A and B, A and C, etc, then we have removed an essential part of the circles, namely where they all intersect, and we have to add that part again.

Thanks Colby!