SOLUTION: Find the missing probability. P(A)=9/20,P(B)=3/5,P(A∩B)=27/100 ,P(A∪B)=?

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Question 1163363: Find the missing probability.
P(A)=9/20,P(B)=3/5,P(A∩B)=27/100 ,P(A∪B)=?
Answer by Theo(13342) About Me  (Show Source):
You can put this solution on YOUR website!
p(a union b) = p(a) + p(b) - p(a intersect b)
therefore:
p(a union b) = 9/20 + 3/5 - 27/100
multiply both sides of this equation by 100 to get:
100 * p(a union b) = 45 + 60 - 27 = 78
divide both sides by 100 to get:
p(a union b) = 78/100 = 39/50
that's your solution.