Latest Miscellaneous Company Exam Aptitude Question SOLUTION: A bag contains 5 red, 4 blue and M green balls if the probability of getting both the balls green, when two balls are selected at random is 1/7, find M

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Miscellaneous Company Exam Question Papers:

(#M40002384) MISCELLANEOUS COMPAN question probability Keep an EYE

A bag contains 5 red, 4 blue and M green
balls if the probability of getting both the balls
green, when two balls are selected at
random is 1/7, find M

Asked In Miscellaneous Company Exam akshay tr (12 years ago)

Unsolved Read Solution (1)

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Read Solution (1) :

rohit  (8 years ago)

we have to select 2 balls and it will be green so we will select two balls from green balls
so

mC2/m+9C2=1/7
on solving

(m! / (m-2! * 2!) ) / (m+9! / (m+7! * 2!) ) =1/7 From nCr=n! / r!*(n-r)!
on solving
(m! / (m-2)! ) * ( (n-7)! / (n+7)!) =1/7

after solving and cross multiplication
m^2+4m-12=0
on solving
m=2,-6
so m will be 2.. Ans

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