Solve the following linear programming problem graphically: Maximize and minimize \( Z = 4x + 2y - 7 \) subject to the constraints \( x + 3y \le 60, x + y \ge 10, x - y \le 0, x \ge 0, y \ge 0 \).
Correct Answer: Max Value \( Z = 73 \) at \( (15, 15) \); Min Value \( Z = 13 \) at \( (5, 5) \). (Based on standard corner point analysis)