Practicing Success

Target Exam

CUET

Subject

-- Mathematics - Section A

Chapter

Applications of Derivatives

Question:

Which of the following is a vertex of positive region bounded by the inequalities :

$4x+y ≥80; 2x+y ≥60; x, y ≥ 0$

Options:

(0, 30)

(80, 0)

(40, 10)

(10, 40)

Correct Answer:

(10, 40)

Explanation:

The correct answer is Option (4) → (10, 40)

plotting $4x+y=80$

  x     20     0  
y 0 80

$2x+y=60$

  x     30     0  
y 0 60

Point of intersection 

$4x+y=80$    ...(1)

$2x+y=60$   ...(2)

eq. (1) - eq. (2)

$4x+y-22x-y=80-60$

$2x=20$

$x=10$ from (1)

$20x+y=60$

$y=40$

(10, 40) is one such vertex