Question

What is the probability of getting 3 white balls in a draw of balls from a box containing 5 white and 4 black

balls.​

Answer 1

we have to find the probability of getting 3 white ball in a draw of balls from a box containing 5 white and 4 black balls.

solution : number of ways of selecting 3 white balls out of 5 white balls = ⁵C₃ = 5!/{3! × (5 - 3)!}

= (5 × 4 × 3!)/{3! × 2!} = 10

number of ways of selecting 0 black balls out of 4 black balls = ⁴C₀ = 4!/4! 0!= 1

Therefore total number of ways of selecting 3 white balls , n(E) = ⁵C₃ × ⁴C₀ = 10 × 1 = 10

total number of ways of selecting 3 balls out of (5 + 4) balls , n(S) = $^9C_3$ = 9!/(3! × 6!) = (9 × 8 × 7)/(6) = 84

probability of getting 3 white balls = n(E)/n(S) = 10/84 = 5/42

Therefore probability of getting three white balls is 5/42

Answer 2

Answer:

5/42 ans

Explanation:

hope it helps you