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probability ques
by anila . - Saturday, 12 March 2011, 06:04 PM
 

TG sir plz help

If 2 different representatives are to be selected at random from a group of 10 employees and if p is the probability that both representatives selected will be women, is p >1/2 ?

(1) More than 1/2 of the 10 employees are women.

(2) The probability that both representatives selected will be men is less than 1/10.

 

 

 

Re: probability ques
by nikita dhanuka - Wednesday, 11 May 2011, 11:47 PM
  Hi Anila smile

the answer should be E i.e, both the statements taken together are also not sufficient.

explanation:
let us try and find out the worst case scenario in each case. if the worst possible probability, P(min) > 1/2 , then we can answer the question...otherwise not.

(1) min no. of women = 6
P(min) = C(6,2)/C(10,2) = 1/3 which is less than 1/2
Hence, we cannot answer the question.

(2) let there be x men. then probability of selecting both men is
C(x,2)/C(10,2) less than 1/10
x <4 /> min no. of women = 7
P(min) = C(7,2)/C(10,2) = 7/15 which is less than 1/2
Hence, we cannot answer

Even on combining both statements, no new information is gathered. min no. of women is still 7. Hence question cannot be answered with both statements. So, the answer is option E.

Cheers smile
Nikita