Answer:
210 ways
Step-by-step explanation:
Given
[tex]n = 7[/tex] --- total
[tex]r = 3[/tex] --- selection
Required
In how many ways can be selection be done
Since orders does matter, then it is permutation.
This is calculated as:
[tex]^nP_r = \frac{n!}{(n-r)!}[/tex]
So, we have:
[tex]^7P_3 = \frac{7!}{(7-3)!}[/tex]
[tex]^7P_3 = \frac{7!}{4!}[/tex]
Solve each factorial
[tex]^7P_3 = \frac{7*6*5*4!}{4!}[/tex]
[tex]^7P_3 = 7*6*5[/tex]
[tex]^7P_3 = 210[/tex]