Question

A bag contains 5 white, 6 red and 4 blue balls. Determine the number of ways in which 2 white, 3 red and 2 blue balls can be selected.​

Answer 1

Let S be the sample space.

Then, n(S) = number of ways of drawing 3 balls out of 15 =

15

C

3

⟹=

3×2×1

(15×14×13)

=455

Let E = event of getting all the 3 red balls.

n(E)=

5

C

3

=

3×2×1

(5×4×3)

=10

Hence, the probability that all of them are red, is:

P(E)=

n(S)

n(E)

=

455

10

=

91

2