SOLUTION: Suppose that a certain college class contains 65 students. Of these, 37 are juniors, 38 are history majors, and 5 are neither. A student is selected at random from the class. (a)

Question 1174934: Suppose that a certain college class contains 65 students. Of these, 37 are juniors, 38 are history majors, and 5 are neither. A student is selected at random from the class. (a) What is the probability that the student is both a junior and a history major? (b) Given that the student selected is a junior, what is the probability that he is also a history major?
Answer by ikleyn(52802) (Show Source): You can put this solution on YOUR website!
.


(a) From one side,  P(or) = 1 -  = .


    From the other side,


        P(or) = P(junior) + P(history) - P(both),

    or

        =  +  - P(both).


    THEREFORE,

       P(both) =  =  = .    ANSWER



(b)   P(junior|history) =  =  =  = .    ANSWER

Solved. // All questions are answered.

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