Frank does a weekly exercise program consisting of cardiovascular work and weight training. Each week, he exercises for at least 6 hours. He spends at most 12
hours on weight training. He spends at most 3 hours doing cardiovascular work. Letx denote the time (in hours) that Frank spends doing cardiovascular work.
Let y denote the time (in hours) that he spends on weight training. Shade the region corresponding to all values of x and y that satisfy these requirements.