A survey of 120 students 60 only have stereos 40 only have c

A survey of 120 students. 60 only have stereos. 40 only have computers. 15 have both. 5 have neither.

A. If a student is selected at random. what is the probability that the student doesn have a computer given that the student has a stereo?

B. The probability that the student have a stereo given that the student has a computer.

Solution

a) probability that the student doesn\'t have a computer given that the student has a stereo = prob doesn\'t have a computer and having a stereo / prob of having stereo

                                                                                                   = (60 / 120) / (75 / 120)

                                                                                                   = 60 / 75 = 0.8

b) probability that the student have a stereo given that the student has a computer= prob of having stereo and having a computer / prob of having a computer

                                                                                               = (15 / 120) / (40 / 120)

                                                                                               = 15 / 40 = 0.375