Question:
A bag contains 4 white, 5 red and 6 blue balls. Three balls are drawn at random from the bag. The probability that all of them are red, is:
[A].
A bag contains 4 white, 5 red and 6 blue balls. Three balls are drawn at random from the bag. The probability that all of them are red, is:
[A].
1 |
22 |
[B].
3 |
22 |
[C].
2 |
91 |
[D].
2 |
77 |
Answer: Option C
Explanation:
Let S be the sample space.
Then, n(S) | = number of ways of drawing 3 balls out of 15 | |||
= 15C3 | ||||
|
||||
= 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 |