Total number of balls =8+6+4=18 Total number of ways of drawing 3 balls out of 18
=18C3=
18!
15!3!
=
18×17×16
3×2
=3×17×16
In order to get 3 different coloured balls, we need to select 1 black out of 8 black balls, 1 red out of 6 red balls and 1 white out of 4 white balls. ∴ Number of ways of getting 3 different coloured balls =8C1×6C1×4C1=8×6×4 ∴ Required probability =