Question

A bag contains 4 white 5red and 6 blue balls. 3balls are drawn at random from the bag. What is the probability that 2 of them are red???

Answer 1

Answer:

Let S be the sample space.

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

15

C 3

15C3

=

15*14*13

3*2*1

15*14*133*2*1= 455.

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

n(E) =

5

C 3

5C3

=

5*4

2*1

5*42*1

= 10.

=> P(E) = n(E)/n(S) = 10/455 = 2/91.