In the next Olympics, the United States can enter four athletes in the diving competition. How many different teams of four divers can be selected from a group of nine divers?


a. 36

b. 6,561

c. 126

d. 3,024

Respuesta :

Answer:

The correct option is C.

Step-by-step explanation:

From the given information it is clear that the total number of divers in a group is 9.

The number of selected divers is 4.

The total ways to select r items from total n item is

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

Using this combination formula, the number of different teams of four divers that can be selected from a group of nine divers is

[tex]^9C_4=\frac{9!}{4!(9-4)!}[/tex]

[tex]^9C_4=\frac{9!}{4!5!}[/tex]

[tex]^9C_4=\frac{9\times 8\times 7\times 6\times 5!}{4\times 3\times 2\times 1\times 5!}[/tex]

Cancel out common factors.

[tex]^9C_4=126[/tex]

Therefore the correct option is C.

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