Problem:
A team of 6 members is to be selected from a group of 7 men and 5 women. How many different teams can be formed if the team must include at least 3 women?
Answer Choices:
A. 540
B. 580
C. 612
D. 700
E. 462
Solution:
To determine the number of different teams that can be formed with at least 3 women, we calculate the possibilities for each case and sum them.
Case 1: 3 Women and 3 Men
- Number of ways to choose 3 women from 5:
\(\)
\[
5C3 = \frac{5!}{3!(5-3)!} = 10
\]
- Number of ways to choose 3 men from 7:
\[
7C3 = \frac{7!}{3!(7-3)!} = 35
\]
- Total teams for this case:
\[
10 \times 35 = 350
\]
Case 2: 4 Women and 2 Men
- Number of ways to choose 4 women from 5:
\[
5C4 = \frac{5!}{4!(5-4)!} = 5
\]
- Number of ways to choose 2 men from 7:
\[
7C2 = \frac{7!}{2!(7-2)!} = 21
\]
- Total teams for this case:
\[
5 \times 21 = 105
\]
Case 3: 5 Women and 1 Man
- Number of ways to choose 5 women from 5:
\[
5C5 = \frac{5!}{5!(5-5)!} = 1
\]
- Number of ways to choose 1 man from 7:
\[
7C1 = \frac{7!}{1!(7-1)!} = 7
\]
- Total teams for this case:
\[
1 \times 7 = 7
\]
Total Number of Teams:
Summing the results from all cases:
\[
350 + 105 + 7 = 462
\]
Final Answer:
E. 462