The number of combinations of x objects chosen from n is equal to the number of combinations of
(n - x)objects chosen from n,where 1 ≤ x ≤ (n - 1).

Question

Quizplus · Accepted Answer

This is a property of combinatorics known as the complement rule. It states that choosing x objects from a set is the same as choosing (n - x) objects from the same set, since the objects not chosen for the first group are automatically chosen for the second group.

The Number of Combinations of X Objects Chosen from N