When randomly selecting an adult, let b represent the event of randomly selecting someone with type b blood. write a sentence describing what the rule of complements below is telling us. upper p left parenthesis upper b or upper b overbar right parenthesisequals1?

The upper bar over B means not B, so the given rule is: P (B or not B) = 1.

The sentence is:

The probability of having type B blood or not having this type of blood is 1, because the two events, having B blood and not having B blood, are complementary, meaning that they constitute the whole universe.