IndiaBIX

Aptitude - Probability - Discussion

Discussion Forum : Probability - General Questions (Q.No. 7)
Probability
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:
21
46
25
117
1
50
3
25
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 `
= (25 x 24 x 23)
(3 x 2 x 1)
= 2300.

n(E) = (10C1 x 15C2)
= 10 x (15 x 14)
(2 x 1)
= 1050.

P(E) = n(E) = 1050 = 21 .
n(S) 2300 46

Discussion:
54 comments Page 5 of 6.
Daniel ocen said:   3 months ago
I can't understand this, someone help me to get it.
Chandni said:   10 years ago
Can anybody tell me why are they using 25C3?
Kathir lee said:   9 years ago
@ Sanjana.

Thank you for the explanation.
Bhargavi said:   7 years ago
On which table 1050/2300 can be divisible?
(2)
Thanos said:   5 years ago
@Jay Lee Lord.

Thank You for your answer.
Mahesh babu said:   1 decade ago
Because he asked 10 girls (and) 15 boys.
Mary-ann said:   10 years ago
I can't understand someone help.
Yugesh said:   1 decade ago
Why do you multiply 24x25x23?
Prabhat said:   1 decade ago
Nice explanation sanjana.
Azly said:   9 years ago
Thank you! @Sanjana.
Post your comments here:

Your comments will be displayed after verification.

Quick links
Quantitative Aptitude
Verbal (English)
Reasoning
Programming
Interview
Placement Papers