SOLUTION: In a study of internet users, researchers discovered that 80% of users own at least one computer ans that 25% of users log onto the internet for more that 30 hrs per week. Suppose

Algebra ->  Probability-and-statistics -> SOLUTION: In a study of internet users, researchers discovered that 80% of users own at least one computer ans that 25% of users log onto the internet for more that 30 hrs per week. Suppose       Log On


   

Question 584957: In a study of internet users, researchers discovered that 80% of users own at least one computer ans that 25% of users log onto the internet for more that 30 hrs per week. Suppose that 15% of users own at least one computer AND log onto the internet for more that 30 hrs per wk. Given that an internet user owns at least one computer, what is the probability that he\she logs onto the internet for more than 30hrs per week?
I know that P(I and C) = P(I) X P(I|C) but I am having trouble figuring out the numbers.
Thank you
Answer by jim_thompson5910(35256) About Me  (Show Source):
You can put this solution on YOUR website!
P(I|C) = P(I and C)/P(C)

P(I|C) = 0.15/0.8

P(I|C) = 0.1875


So the probability that the user logs on for more than 30 hrs a week, given that the internet user owns at least one computer, is 0.1875 (which is an 18.75% chance)