Question

Let A denote the event that a disk has high shock resistance, and let B denote the event that a disk has high scratch resistance. If a disk is selected at random, determine the following probabilities. Input your answers in the fractional form (do not simplify).P(A)=86/100

P(B)=79/100
P(A')=7/50
P(A U B)=95/100
P(A' U B)= ???

Answer 1

P(A' U B) = 84/100

Explanation:

We have, P(A) = 86/100

P(B) = 79/100

P(A') = 7/50

P(A U B) = 95/100

-: P(A intersection B) = P(A) + P(B) - P(A U B)

P(A intersection B) = 86/100 + 79/100 - 95/100

P(A intersection B) = (86+79-95)/100 = (165-95)/100

P(A intersection B) = 70/100

Now, P(A' U B) = P(A') + P(A intersection B)

P(A' U B) = 7/50+70/100

P(A' U B) = (7*2+70)/100 = (14 + 70)/100

P(A' U B) = 84/100