Q3. The cost of hiring a company that offers catering services to serve food for a birthday party is 150$ per head for less than or equal to 20 persons, 120$ for 21 to 50 persons and 110$ per head for 51 to 100 persons. For more than 100 persons the cost is 80$ per head. Represent the total cost as a piecewise function of the number of attendees of the birthday party. Sketch the graph