Aptitude - Probability - Discussion

Discussion Forum : Probability - General Questions (Q.No. 12)
12.
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:
1
22
3
22
2
91
2
77
Answer: Option
Explanation:

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

Discussion:
33 comments Page 4 of 4.

Priya said:   1 decade ago
Can anyone explain clearly?

Rohit jadhav said:   1 decade ago
Ya dinesh is right.

Adu said:   8 years ago
Thanks all.


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