ProbabilityHard
Question
Seven white balls and three black balls are randomly placed in a row. The probability that no two black balls are placed adjscently, equals
Options
A.

B.

C.

D.

Solution
The number of ways of placing 3 balls without any restriction is 10C3 . Since, we have total 10 places of putting 10 balls in a row . Now the number of ways in which no two black balls put together is equal to the number of ways of choosing 3 places marked ′
′ out of eight places.

This can be done in 8C3 ways.
∴ Rwquired probability
′ out of eight places. 
This can be done in 8C3 ways.
∴ Rwquired probability

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