Answer 1

Total number of balls = 10 + 4 + 6 = 20.

One ball can be drawn from 20 balls in ²⁰C₁ = 20 ways

∴ n(S) = 20

Let C ≡ the event that ball drawn is non-black ball. There are 14 non-black balls. One ball can be drawn from these in ¹⁴C₁ =14 ways.

∴ n(C) = 14

∴ the required probability = P(C)

= `("n"("C"))/("n"("S"))`

= `14/20`

= `7/10`