Jason inherited a piece of land from his great-uncle. Owners in the area claim that there is a 45% chance that the land has oil. Jason decides to test the land for oil. He buys a kit that claims to have an 80% accuracy rate of indicating oil in the soil. What is the probability that the land has oil and the test predicts that there is no oil?

Question

cruffo · Answer

the two events are independent
A =  the land has oil 
B =  the kit is not accurate

P(A and B) = P(A) * P(B)

anonymous · Answer

@SithsAndGiggles  so this one would be the same thing u just did?

anonymous · Answer

@jcr268 yeah this is the exact same question.

anonymous · Answer

is says at the end of the problem that the test predicts that there is no oil, the other one would be test predicts oil

anonymous · Answer

Oh right, small detail. So instead of $P(A\cap K)$, you want to find $P(A\cap K')$, which is 
$$P(K'|A)P(A)=0.20\times0.45=0.09$$