Question 14601: A class of twenty students consists of eight males and twelve females. Two students are selected at random. By considering the events A=' the first student is male' and B= 'the second student is male' evaluate the possibilities of these events:
a) C= 'both students are male'
b) D= 'both students are female'
c) E= 'one male and one female chosen'
Please could you help me with the question above, I know that the probability of selecting a male first is 8/20 and selecting second is 7/19, but would appreciate it if someone could help me how to work out the other events.
Thanks
Sam
Answer by longjonsilver(2297)   (Show Source):
You can put this solution on YOUR website! P(both male) = 8/20 * 7/19 = 14/95
P(both female) = 12/20 * 11/19 = 33/95
P(one male and one female) is all the other possibilities, so if you are feeling secure in your maths skills, you can just say 1 - (14/95 + 33/95)
--> 1 - (47/95)
--> 48/95
Now, if you didn't know this, you would just have to work it out fully as:
P(first male then female) + P(first female then male)
(8/20 * 12/19) + (12/20 * 8/19)
24/95 + 24/95
48/95
jon.
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