We have been given that there are 8 different types of chips at Subway. We are asked to find the number of different ways to choose 2 of them.
We will use combinations to solve our given problem.
Number of combinations of r objects chosen from n objects is given by [tex]C(n,r)=\frac{n!}{r!(n-r)!}[/tex]
[tex]C(8,2)=\frac{8!}{2!(8-2)!}[/tex]
[tex]C(8,2)=\frac{8\cdot 7\cdot 6!}{2\cdot 1\cdot 6!}[/tex]
[tex]C(8,2)=\frac{8\cdot 7}{2}[/tex]
[tex]C(8,2)=4\cdot 7[/tex]
[tex]C(8,2)=28[/tex]
Therefore, you can choose 2 of them in 28 different ways.
