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.
Person said:
9 years ago
There are three probabilities, BBG, BGB and GBB. The chance of getting 2 boys and 1 girl is 15/25 X 14/24 X 10/23 which is 7/46. Since there are three ways to get 2 boys and a Girl,
7/46 X 3 = 21/46.
7/46 X 3 = 21/46.
(2)
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.
Al Ford said:
1 decade ago
I have a similar problem. Can anyone explain how to answer this: A class contains 7 women and 7 men. Suppose we choose three random students. How many ways can we choose exactly 1 woman?
Anony said:
9 years ago
Why is it not solved like this?
Total possible combinations - BBB, GGG, BGB, BBG, GBB, GGB, GBG, BGG i.e. 8.
Fav combination: GBB, BGB, BBG so 3.
So the answer should be 3/8.
Total possible combinations - BBB, GGG, BGB, BBG, GBB, GGB, GBG, BGG i.e. 8.
Fav combination: GBB, BGB, BBG so 3.
So the answer should be 3/8.
Shyam said:
1 decade ago
@Abhi.
I have the same problem. I am getting 7/46 But by formula the answer is given as 21/46. I solved it by (10/25) * (15/24) * (14/23).
Please anyone explain on this query.
I have the same problem. I am getting 7/46 But by formula the answer is given as 21/46. I solved it by (10/25) * (15/24) * (14/23).
Please anyone explain on this query.
Nemi said:
1 decade ago
If there are 5 men and some women in a group. If the probability to select two Girls out of all is 3/20 then find the number of Girls in a group. Give answer if any one know.
Asc said:
1 decade ago
@Abhi.
You got this wrong when you took only one girl as the first solution. You could also have one boy and another boy as the first student chosen i.e 1.
You got this wrong when you took only one girl as the first solution. You could also have one boy and another boy as the first student chosen i.e 1.
Lesly said:
8 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.
AnnieVal said:
9 years ago
Please solve this: " A school contains 750 boys and 450 girls. If a pupil is chosen at random what is the probability that a girl is chosen?".
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.
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