An urn contains 9 balls two of which are rd, three blue and four black. Three balls are drawn at random. the probability that they are of the same colour is a. 5/84            b. 3/9            c. 3/7          d. 7/17

Explanation

Three balls can be drawn randomly from nine balls in `9_(C_3)=84` ways.c


Three balls cannot be red as there are only two red balls.


Three balls of the same colour can be drawn in the following ways :


3 blue out of a total of 3 blue balls.


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