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 6 of 6.
Mahesh babu said:
1 decade ago
Because he asked 10 girls (and) 15 boys.
Gnana said:
1 decade ago
I too have same doubt. Can any one clarify this, soon.
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?
Prabhu said:
1 decade ago
(10C1 x 15C2) why they are multiplying this ?
They should add the value know .. 10 c1 + 15 c2
They should add the value know .. 10 c1 + 15 c2
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