217k views
3 votes
I am having trouble with this problem, could you pleas explain it to me. Thank you.

I am having trouble with this problem, could you pleas explain it to me. Thank you-example-1
User Mcousillas
by
5.5k points

1 Answer

3 votes

There are a total of 6 lettered buttons on the controller. Since the special moves require two buttons pressed at the same time, the order does not matter. We therefore get


\begin{gathered} \binom{6}{2}=(6!)/(2!(6-2)!) \\ \binom{6}{2}=\frac{6\cdot5\operatorname{\cdot}4\operatorname{\cdot}3\operatorname{\cdot}2\operatorname{\cdot}1}{(2\operatorname{\cdot}1)(4!)} \\ \binom{6}{2}=\frac{720}{2(4\cdot3\operatorname{\cdot}2\operatorname{\cdot}1)} \\ \binom{6}{2}=(720)/(2(24)) \\ \binom{6}{2}=(720)/(48) \\ \binom{6}{2}=15 \end{gathered}

Therefore, there are a total of 15 possible combinations.

User DinhNgocHien
by
5.6k points