The science club has five female and five male students. The club will randomly select two people to compete in an upcoming science competition.

What is the probability that both people chosen are females?

A. [tex]$\frac{1}{90}$[/tex]
B. [tex]$\frac{1}{5}$[/tex]
C. [tex]$\frac{2}{9}$[/tex]
D. [tex]$\frac{1}{4}$[/tex]



Answer :

To find the probability that both people chosen are females, let's solve the problem step by step:

1. Determine the total number of students:
- There are 5 female students and 5 male students.
- Total number of students = [tex]\( 5 + 5 = 10 \)[/tex].

2. Calculate the total number of ways to choose 2 students out of 10:
- We use the combination formula [tex]\( \binom{n}{r} \)[/tex] which represents the number of ways to choose [tex]\( r \)[/tex] items from [tex]\( n \)[/tex] items without regard to the order.
- Here, [tex]\( n = 10 \)[/tex] and [tex]\( r = 2 \)[/tex].
- [tex]\[ \binom{10}{2} = \frac{10!}{2!(10-2)!} = \frac{10 \times 9}{2 \times 1} = 45 \][/tex]

3. Calculate the total number of ways to choose 2 female students out of 5:
- Here, [tex]\( n = 5 \)[/tex] and [tex]\( r = 2 \)[/tex].
- [tex]\[ \binom{5}{2} = \frac{5!}{2!(5-2)!} = \frac{5 \times 4}{2 \times 1} = 10 \][/tex]

4. Calculate the probability:
- The probability of an event is given by the ratio of the number of favorable outcomes to the total number of possible outcomes.
- The number of favorable outcomes is the number of ways to choose 2 females from 5, which we calculated as 10.
- The total number of possible outcomes is the number of ways to choose 2 students from 10, which we calculated as 45.
- [tex]\[ \text{Probability} = \frac{\text{Number of favorable outcomes}}{\text{Total number of possible outcomes}} = \frac{10}{45} = \frac{2}{9} \][/tex]

Therefore, the probability that both people chosen are females is [tex]\( \frac{2}{9} \)[/tex].

So, the correct answer is:
[tex]\[ \frac{2}{9} \][/tex]