Here are the solutions for Exercise 1:
Exercise 1: How many ways can you form a 4-person committee from 6 men and 5 women?
Total number of people = 6 men + 5 women = 11 people.
The committee size is 4 people.
a) With no restrictions
Step 1: Determine the total number of people (n) and the committee size (k).
n=11 (total people)
k=4 (committee members)
Step 2: Use the combination formula, as the order of selection does not matter for a committee.
C(n,k)=(kn)=k!(n−k)!n!
Step 3: Substitute the values and calculate.
C(11,4)=4!(11−4)!11!=4!7!11!
C(11,4)=4×3×2×1×7!11×10×9×8×7!
C(11,4)=4×3×2×111×10×9×8
C(11,4)=247920
C(11,4)=330
The number of ways to form a 4-person committee with no restrictions is 330.
b) the committee has 2 men and 2 women
Step 1: Determine the number of ways to choose 2 men from 6 men.
C(6,2)=2!(6−2)!6!=2!4!6!
C(6,2)=2×1×4!6×5×4!=230=15
Step 2: Determine the number of ways to choose 2 women from 5 women.
C(5,2)=2!(5−2)!5!=2!3!5!
C(5,2)=2×1×3!5×4×3!=220=10
Step 3: Multiply the number of ways to choose men and women, as these are independent selections.
Total ways = C(6,2)×C(5,2)=15×10=150
The number of ways to form a committee with 2 men and 2 women is 150.
c) the committee has only 1 woman
Step 1: If the committee has only 1 woman, and the committee size is 4, then the remaining 3 members must be men.
Determine the number of ways to choose 1 woman from 5 women.
C(5,1)=1!(5−1)!5!=1!4!5!
C(5,1)=1×4!5×4!=5
Step 2: Determine the number of ways to choose 3 men from 6 men.
C(6,3)=3!(6−3)!6!=3!3!6!
C(6,3)=3×2×1×3!6×5×4×3!=6120=20
Step 3: Multiply the number of ways to choose women and men.
Total ways = C(5,1)×C(6,3)=5×20=100
The number of ways to form a committee with only 1 woman is 100.