Question

The maximum value of $z = 3x + 4y$ subject to the condition $x + y \le 40, x + 2y \le 60, x,y \ge 0$ is

• A. 130
• B. 120
• C. 40
• D. 140

Answer 1

Answer: (D)

140

Answer 2

Obviously, $z = 3x + 4y$ will be maximum at $(20,\, 20)$ $\therefore$ Max $z = 3 ? 20 + 4 ? 20 = 60 + 80 = 140$