Latest Infosys Aptitude Question SOLUTION: A bag contains 2 red, 3 green and 2 blue balls. Two balls are drawn at random. What is the probability that none of the balls drawn is blue? a)10/21 b)11/21 c)2/7 d)5/7

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A bag contains 2 red, 3 green and 2 blue balls. Two balls are drawn at random. What is the probability that none of the balls drawn is blue?
a)10/21
b)11/21
c)2/7
d)5/7

Asked In Infosys (12 years ago)

Unsolved Read Solution (4)

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Dr.Dipin Singh  (12 years ago)

probability that none of the balls drawn is blue = (5/7) *(4/6) = 10/21 ..... option a)

Is this solution Helpfull? Yes (7) | No (15)  

vinodhini  (9 years ago)

(5c2)/(7c2)= 10/21

Is this solution Helpfull? Yes (2) | No (4)  

Madhullapalli Suhasini  (7 years ago)

total no of balls drawn at random=2c2+3c2+2c2=7
taken two balls are none of balls drawn is blue=2c2*3c2*2c2-2c2=1*3*1-1=3-1=2
so p=except blue ball/tot no of balls=2/7

Is this solution Helpfull? Yes | No (2)  

sourav shaw  (4 years ago)

(5c2)/(7c2)=10/21 (answer)
7c2 because 2 balls are drawn from 7 balls.
now the question says that drawn balls are not from blue...so we neglect blue balls...
Now remaining are 2 red and 3 green balls ...in which we have to select 2 balls..
therefore it will be done by 5c2 way...(2 red + 3 green)

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