From a group of 7 men and 6 women , a committee of 5 person with more males than females is to be formed . In how many ways can this be done ?
Step-by-step Solution:
We are asked to find the number of ways to form a 5-person committee from a group of 7 men and 6 women, with the condition that there must be more men than women in the committee.
For a committee of 5, let 'M' be the number of men and 'W' be the number of women. The condition is $M > W$ and $M + W = 5$. This gives us three possible cases:
The total number of ways is the sum of the ways each of these cases can be formed.
We will use the combination formula $C(n, k) = \frac{n!}{k!(n-k)!}$ since the order in which members are chosen does not matter.
Case 1: 3 Men from 7, and 2 Women from 6
Number of ways = $C(7, 3) \times C(6, 2)$
$C(7, 3) = \frac{7!}{3!4!} = \frac{7 \times 6 \times 5}{3 \times 2 \times 1} = 35$
$C(6, 2) = \frac{6!}{2!4!} = \frac{6 \times 5}{2 \times 1} = 15$
Total for Case 1 = $35 \times 15 = 525$
Case 2: 4 Men from 7, and 1 Woman from 6
Number of ways = $C(7, 4) \times C(6, 1)$
$C(7, 4) = \frac{7!}{4!3!} = \frac{7 \times 6 \times 5}{3 \times 2 \times 1} = 35$
$C(6, 1) = \frac{6!}{1!5!} = 6$
Total for Case 2 = $35 \times 6 = 210$
Case 3: 5 Men from 7, and 0 Women from 6
Number of ways = $C(7, 5) \times C(6, 0)$
$C(7, 5) = \frac{7!}{5!2!} = \frac{7 \times 6}{2 \times 1} = 21$
$C(6, 0) = 1$
Total for Case 3 = $21 \times 1 = 21$
The total number of ways to form the committee is the sum of the ways for each valid case:
Total Ways = 525 + 210 + 21 = 756