An urn contains 4 white and 3 red balls. Find the probability distribution of the number of red balls in a random draw of three balls.

Explanation

Here , Three bals are taken out of an urn

Sample space is

={S}({RRR}, {RRW}, {RWR}, {WRR}, {RWW}, {WRW}, {WWR}, {WWW})

Where R represents red ball and W, white ball

Let {X}= number of red balls.

so possible value of {X} are 3,2,1,2,1,0 or 0,1,2,3 (no red ball)

{P}({X}=0)={P}( No red ball )={P}({WWW})

`=frac{4}{7} times =frac{4}{35}`

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