Using the combination formula, it is found that photos of 9 different chairs were shown to the home owner.
The order in which the chairs are chosen is important, hence, the <em>permutation formula </em>is used to solve this question.
<h3>What is the permutation formula?</h3> is the number of different permutations of x objects from a set of n elements, given by:
In this problem, two chairs are chosen from a set of n, and there are 72 different outcomes, hence:
Which is a quadratic function with coefficients , hence:
Taking the positive root:
Photos of 9 different chairs were shown to the home owner.
You can learn more about the permutation formula at brainly.com/question/25925367