Answer: Feedback
Explanation: Feedback is the reaction obtained in the form of information from the task a person has performed or any product. It gives the review of the service that is given by the customer, user etc.The reaction that is obtained can be a negative feedback or positive feedback.
Both types of feedback is necessary because it helps in the improvement of the service. The negative reaction will helps to change/improve the service that is not liked by the customer and positive feedback tells about the services appreciated by the customer. So, Shelby is also keeping the feedbacks for the same purpose for her salon business.
Each of the 20 people has 19 other people to communicate to. If you add that all up you get 20*19 paths, but then each path is counted twice (back and forth), so we divide this by 2. 20*19/2 = 190.
The general forumula is n(n-1)/2
