SOLUTION: The probabilities of the events A and B are .20 and .30, respectively. The probability that both A and B occur is .15. What is the probability of either A or B occurring?

Algebra ->  Rational-functions -> SOLUTION: The probabilities of the events A and B are .20 and .30, respectively. The probability that both A and B occur is .15. What is the probability of either A or B occurring?      Log On


   

Question 361388: The probabilities of the events A and B are .20 and .30, respectively. The probability that both A and B occur is .15. What is the probability of either A or B occurring?
Answer by neatmath(302) About Me  (Show Source):
You can put this solution on YOUR website!
We are given P(A)=.2 P(B)=.3 P(A and B)=.15

The probability that A or B occurs is the probability of A plus the probability of B, minus the probability of both A and B.

Events A & B are NOT mutually exclusive since P(A and B) is NOT equal to zero.

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

P(A or B) = .2 + .3 - .15

P(A or B) = .35

As a note, if events A and B WERE mutually exclusive, the P(A or B) would just equal P(A) + P(B) only.

I hope this helps!