Consider the Venn Diagram:
• The middle region A ∩ B means the common elements of A and B.
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• The whole region consisting of two circles is known as A U B, or the chances of A and B.
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• The region (A U B)' is the complement of A U B, which is neither A nor B.
We are interest in A and B, thus this is all of the region consisting of the two circles, A and B.
Thus, the probability is:
0.3 + 0.2 + 0.1 = 0.6
Answer
0.6