A train can accommodate at most 80 passengers, economy class (x) and first class (y) passengers. To avoid making a loss the train must carry at least 10 economy class passengers and at least 20 first class passengers. Due to the number of item s the forts class passengers receive, the number of first class passengers should be at most three times the number of economy class passengers. first class tickets cost $5000 while economy class tickets $3000. state or describe what the variable x and y represents. state the objective function. list the constraints.​