Question

Please helpppppp In exercises 3-6, events A and B are disjoint. Find P(A or B).

3. P(A)=0.3, P(B)=0.1
5. P(A)= 1/3, P(B)=1/4
Also if you can be explain how to do these problems i'm home schooled and don't understand at all

Answer 1

Problem 3

Disjoint events are two (or more) events that cannot happen at the same time. An example would be flipping heads and tails at the same time with the same coin. Another example is selecting an ace of spades and selecting an ace of diamonds, when you only select one card.

In general notation, P(A and B) = 0 if and only if A and B are disjoint.

P(A or B) = P(A) + P(B) - P(A and B)

P(A or B) = 0.3 + 0.1 - 0

P(A or B) = 0.4

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Problem 5

Same idea, but different numbers

P(A or B) = P(A) + P(B) - P(A and B)

P(A or B) = 1/3 + 1/4 - 0

P(A or B) = 4/12 + 3/12 - 0

P(A or B) = 7/12