Let S be the sample space.
| Then, n(S) |
= number of ways of drawing 3 balls out of 15 |
|
= 15C3 |
|
| = |
(15 x 14 x 13) |
| (3 x 2 x 1) |
|
|
= 455. |
Let E = event of getting all the 3 red balls.
| ∴ n(E) = 5C3 = 5C2 = |
(5 x 4) |
= 10. |
| (2 x 1) |
| ∴ P(E) = |
n(E) |
= |
10 |
= |
2 |
. |
| n(S) |
455 |
91 |
