Question

What is the minimum value of C = 7x + 8y, given the constraints: 2x + y ≥ 8, x + y ≥ 6, x ≥ 0, y ≥ 0. A. 32 B. 42 C. 46 D. 64

Answer 1

I just took the test and the answer is 42

Answer 2

Answer: The minimum value of C is 46.

Step-by-step explanation:

Since, Here, We have to find out Min C = 7x+8y

Given the constraints are $2x+y\geq 8$ -------(1)

$x+y \geq 6$   ------------- (2)

$x \geq 0$, $y \geq 0$  -------- (3)

Since, For equation 1) x-intercept, (4, 0) and y-intercept (0,8)

And, $2\times 0+0\geq 8$⇒$0\geq 8$ ( false)

Therefore the area of line 1) does not contain the origin.

For equation 2) x-intercept, (6, 0) and y-intercept (0,6)

And, $0+0\geq 6$⇒$0\geq 6$ ( false)

Therefore the area of line 2) does not contain the origin.

Thus after plotting the constraints 1) 2) and 3) we get Open Shaded feasible region AEB ( Shown in below graph)

At A≡(0,8) , C= 64

At E≡(2,4),  C= 46

At B≡(6,0),  C= 42

Thus at B, C is minimum, And its minimum value = 42