Question

Q: Which of the following sets have cardinality 1?

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Answer 1

Let A = {1, 2, 3, 4, 5, 6} and B = {2, 4, 6, 8}.

What is the cardinality of B? A ⋃ B, A ⋂ B?

The cardinality of B is 4, since there are 4 elements in the set.

The cardinality of A ⋃ B is 7, since A ⋃ B = {1, 2, 3, 4, 5, 6, 8}, which contains 7 elements.

The cardinality of A ⋂ B is 3, since A ⋂ B = {2, 4, 6}, which contains 3 elements.