A ski patrol unit has seven members available for duty, and two of them are to be sent to rescue an injured skier. In how many ways can two of these seven members be selected?

Respuesta :

Answer:

21

Step-by-step explanation:

7C2 = 21

The number of ways two of these seven members can be selected is 21

The number of members of the ski patrol unit is given as:

[tex]n = 7[/tex]

The number of members of the ski patrol unit to select is given as:

[tex]r=2[/tex]

To calculate the number of ways the members can be selected, we make use of the following combination formula

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

So, we have:

[tex]^7C_2= \frac{7!}{(7-2)!2!}[/tex]

Simplify the expression

[tex]^7C_2= \frac{7!}{5!2!}[/tex]

Expand each factorial

[tex]^7C_2= \frac{7 \times 6 \times 5!}{5! \times 2 \times 1}[/tex]

Cancel out the factorials

[tex]^7C_2= \frac{7 \times 6 }{2 \times 1}[/tex]

Evaluate the products

[tex]^7C_2= \frac{42}{2}[/tex]

Divide 42 by 2

[tex]^7C_2= 21[/tex]

Hence, the number of ways two of these seven members can be selected is 21

Read more about combination at:

https://brainly.com/question/11732255

ACCESS MORE
ACCESS MORE
ACCESS MORE
ACCESS MORE