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:
Answer: Option
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 |
Discussion:
33 comments Page 4 of 4.
Adnan Baig said:
2 years ago
Here it should be 5c3 becuase the selection of balls is 3 red balls.
(2)
Smrutiranjan Routray said:
2 years ago
Only red ball means;
5/15 * 4/14 * 3/13 = 60/2730 = 2/91.
5/15 * 4/14 * 3/13 = 60/2730 = 2/91.
(5)
Seenivasan said:
11 months ago
5c3 = 5 * 4 * 3/1 * 2 * 3.
Take 3 commons in the above scenario so we can calculate the sum as 5c2.
Take 3 commons in the above scenario so we can calculate the sum as 5c2.
(3)
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