Lasha Posted January 12, 2003 Share Posted January 12, 2003 Hi everybody! Can anybody solve this probability question? In a shipment of 100 televisions, 6 are defective. If a person buys two televisions, what is the probability that both are defective? A)3/100 B) 9/2500 C)1/330 D)None of the above I think the answer is B but the answer key says it's C. Quote Link to comment Share on other sites More sharing options...
Sara Posted January 12, 2003 Share Posted January 12, 2003 In a shipment of 100 televisions, 6 are defective. If a person buys two televisions, what is the probability that both are defective? A)3/100 B) 9/2500 C)1/330 D)None of the above I think the answer is B but the answer key says it's C. Hi Lasha :D I think the answer should be C. Here is my solution. The probability that the first TV is defective is 6/100 or 3/50. Right? However, the probability that the second TV is defective is 5/99. Why? It's because now there are only 5 defective TVs left in the pool of 99 TVs. Ultimately, the final solution is 6/100*5/99 which is 1/330. Quote Link to comment Share on other sites More sharing options...
Lasha Posted January 12, 2003 Author Share Posted January 12, 2003 Yes, you are right Sara. Thank you very much. Quote Link to comment Share on other sites More sharing options...
longlong Posted January 17, 2003 Share Posted January 17, 2003 I don't known about GRE, but I don't think it is a GMAT question. Moreover, the question itself is unclear. It only says out of a 100 TV, 6 is defective. It gives you the average chance of getting a defective TV of 0.06. It doesn't tell you that both TV in deed come from the same shipment. They could, in fact, come from different shipment. Therefore, having the same probability of 0.06 each in getting a bad TV. Under this assumption, the correct answer is B instead of C. Long long Quote Link to comment Share on other sites More sharing options...
asdada1 Posted February 2, 2007 Share Posted February 2, 2007 6c2/100c2 = 1/330 Quote Link to comment Share on other sites More sharing options...
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