(a) There are chairs in a row. Find the number of ways of choosing of these chairs, so that no two chosen chairs are adjacent.
(b) There are 10 chairs in a circle, labelled from 1 to 10. Find the number of ways of choosing 3 of these chairs, so that no two chosen chairs are adjacent.
(c) There are chairs in a circle, labelled from 1 to Find the number of ways of choosing of these chairs, so that no two chosen chairs are adjacent.
Dude 4 questions in a row... what is this... your homework? If so, I recommend you only asking one question and trying to understand the topic. Also, why didn't you do this before today... procrastinating will not be good in the long run