OpenStudy (anonymous):

Your friend randomly selects two movies from your collection to borrow. Your collection includes 9 comedies, 5 dramas, 3 mysteries, 1 musical, and 2 horror movies. What is the probability that both movies are comedies?

OpenStudy (kropot72):

Initially there are 20 movies to choose from. On the first selection the probability of choosing a comedy is 9/20. If a comedy was selected on the first selection, there will be 8 comedies in a total of 19 movies; so the probability of choosing another comedy is 8/19. Therefore the probability that both movies are comedies is given by: \[P(2\ comedies)=\frac{9\times8}{20\times19}=you\ can\ calculate\]

OpenStudy (anonymous):

72/380?

OpenStudy (kropot72):

You are correct so far, but you need to simplify the fraction by dividing the numerator and the denominator by 4.