Respuesta :

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]

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