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A box contains 5 red, 4 blue and an unkn...

A box contains 5 red, 4 blue and an unknown number `'n'` of green balls. If probability of both balls being green, when 2 balls are selected from the box, is `1/7`, then `n=`

A

1

B

6

C

10

D

12

Text Solution

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The correct Answer is:
B
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