CBSE Class 11-science Answered

Since balls of same color are such that we can distinguish them, therefore we have 6 different red balls, 5 different black balls and 5 different green balls.

Here we have to select 3 balls of each color and so a total of 9 balls. 

The number of ways of selecting 3 red balls from 6 different red balls.

The number of ways of selecting 3 black balls from 5 different black balls

Similarly the number of ways of selecting 3 green balls out of 5 different green balls

Hence, the required number of selecting 9 balls = 20 x 10 x 10 = 2000 ways