Aptitude - Probability - Discussion
Discussion Forum : Probability - General Questions (Q.No. 7)
7.
In a class, there are 15 boys and 10 girls. Three students are selected at random. The probability that 1 girl and 2 boys are selected, is:
Answer: Option
Explanation:
Let S be the sample space and E be the event of selecting 1 girl and 2 boys.
| Then, n(S) | = Number ways of selecting 3 students out of 25 | |||
| = 25C3 ` | ||||
|
||||
| = 2300. |
| n(E) | = (10C1 x 15C2) | ||||||
|
|||||||
| = 1050. |
 P(E) = |
n(E) | = | 1050 | = | 21 | . |
| n(S) | 2300 | 46 |
Discussion:
54 comments Page 3 of 6.
Lesly said:
9 years ago
If there are 4 children in a family, what is the probability that the family has an equal number of boys and girls, at least 2 boys?
Please answer it.
Please answer it.
Kuldeep said:
8 years ago
Thanks @Sanjana.
Shikha said:
8 years ago
I am not able to understand this answer please some one clear my doubt.
Sanu said:
8 years ago
We don't have to use nCr here it should be nPr.
We are only selecting the girls and not arranging, so no need of using combination here.
We are only selecting the girls and not arranging, so no need of using combination here.
Deel khus said:
8 years ago
@Prabhu.
They are multiplied bc.
The rule of calculating probability is that if getting a or b then we must be added the probability and if getting a and b then its probability must be multiplied.
They are multiplied bc.
The rule of calculating probability is that if getting a or b then we must be added the probability and if getting a and b then its probability must be multiplied.
Shekhar Gupta said:
8 years ago
To select boy and girls are mutually independent events. So they are multiplied.
Thanos said:
6 years ago
@Jay Lee Lord.
Thank You for your answer.
Thank You for your answer.
Annie said:
1 decade ago
@Abhi
Because we do not care about the order in which we pick the boys and girls.
Also, if you picked the boys and girls in a different order than the one you used, wouldn't it be a different answer? So we don't solve it like x/25 x y/24 x z/23
Because we do not care about the order in which we pick the boys and girls.
Also, if you picked the boys and girls in a different order than the one you used, wouldn't it be a different answer? So we don't solve it like x/25 x y/24 x z/23
Priya said:
1 decade ago
@prabhu.
Even I have the same doubt. Can some intellectual person answer this?
Even I have the same doubt. Can some intellectual person answer this?
Gnana said:
1 decade ago
I too have same doubt. Can any one clarify this, soon.
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