TS ICET 2017 Question Paper with Solutions for online practice

Total number of balls $=8+6+4=18$
Total number of ways of drawing 3 balls out of 18 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 ${=}^8{\mathit{C}}_1{\times }^6{\mathit{C}}_1{\times }^4{\mathit{C}}_1=8\times 6\times 4$
∴ Required probability $=\frac{8\times 6\times 4}{3\times 17\times 16}=\frac{4}{17}$