A group of 3 students is to be chosen from a 32-member class to represent the class on the student council.How many ways can this be done? (NOTE: Order of the selection is not important.)Answer:ways

Respuesta :

Permutation -- Order matters

Combination -- Order doesn't matter

For the question, order does not matter. Hence, we have a combination.

The number of ways to select 3 students from 32 students is 32C3.

To evaluate "32C3", we need to know the combination formula:

[tex]^nC_r=\frac{n!}{(n-r)!r!}[/tex]

Let's evaluate 32 C 3,

[tex]\begin{gathered} ^nC_r=\frac{n!}{(n-r)!r!} \\ ^{32}C_3=\frac{32!}{(32-3)!3!} \\ =\frac{32\cdot31\cdot30\cdot29!}{29!\cdot3!} \\ =\frac{32\cdot31\cdot30\cdot\cancel{29!}}{\cancel{29!}\cdot3!} \\ =\frac{32\cdot31\cdot30}{3\cdot2\cdot1} \\ =4960 \end{gathered}[/tex]Answer

4960