Question

In Salem, 82% of the households have cable television and Internet access and 90% of the houses have cable television. What is the probability that a house has Internet access given that it has cable television?
A) 8%
B) 67%
C) 73%
D) 91%

Answer 1

The formula for conditional probability is:
$P(A|B)=\frac{P(A\cap B)}{P(B)}$
$P(I|C)=\frac{P(I\cap C)}{P(C)}=\frac{0.82}{0.90}=0.91$
The correct answer choice is therefore D) 91%

Answer 2

The answer is D. 91%