Explanation
In the question we are given that the possible letters williams can pick from is letters A, B, C, D and E.
Since he is selecting two letters from the given five, we can use the formula for combination to find the number of 2-button special moves that are possible with the controller
Therefore we will have;
[tex]\begin{gathered} ^nC_r=\frac{n!}{(n-r)!r!} \\ \text{Where n = 5 and r=2} \end{gathered}[/tex]
Hence,
[tex]^5C_2=\frac{5!}{3!2!}=\frac{5\times4\times3\times2\times1}{3\times2\times1\times2\times1}=5\times2=10[/tex]
Answer: 10 combinations
