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The maximum and minimum values of Z= 5x+...

The maximum and minimum values of `Z= 5x+2y`, subject to the constraints `2x+3y ge 3, x-2y ge 2, 6x+4y le 24, -3x+2y le 3" and "x, y ge 0`, are respectively

A

`(18)/(7), (2)/(7)`

B

`(19, (63)/(13)`

C

`19, 63`

D

`19, 13`

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To solve the problem of finding the maximum and minimum values of \( Z = 5x + 2y \) subject to the given constraints, we will follow these steps: ### Step 1: Identify the constraints The constraints given are: 1. \( 2x + 3y \geq 3 \) 2. \( x - 2y \geq 2 \) 3. \( 6x + 4y \leq 24 \) 4. \( -3x + 2y \leq 3 \) 5. \( x \geq 0 \) 6. \( y \geq 0 \) ### Step 2: Convert inequalities into equations To find the feasible region, we convert the inequalities into equations: 1. \( 2x + 3y = 3 \) 2. \( x - 2y = 2 \) 3. \( 6x + 4y = 24 \) 4. \( -3x + 2y = 3 \) ### Step 3: Find intersection points of the lines We will find the intersection points by solving pairs of equations: 1. **Intersection of \( 2x + 3y = 3 \) and \( x - 2y = 2 \)**: - From \( x - 2y = 2 \), we can express \( x = 2 + 2y \). - Substitute into \( 2(2 + 2y) + 3y = 3 \): \[ 4 + 4y + 3y = 3 \implies 7y = -1 \implies y = -\frac{1}{7} \quad (\text{not feasible since } y \geq 0) \] 2. **Intersection of \( 2x + 3y = 3 \) and \( 6x + 4y = 24 \)**: - From \( 6x + 4y = 24 \), simplify to \( 3x + 2y = 12 \). - Multiply \( 2x + 3y = 3 \) by 2: \[ 4x + 6y = 6 \] - Now solve: \[ 3x + 2y = 12 \quad \text{and} \quad 4x + 6y = 6 \] - Using elimination or substitution, we find: \[ y = 0 \implies x = 4 \quad (4, 0) \] 3. **Intersection of \( x - 2y = 2 \) and \( 6x + 4y = 24 \)**: - Substitute \( x = 2 + 2y \) into \( 6(2 + 2y) + 4y = 24 \): \[ 12 + 12y + 4y = 24 \implies 16y = 12 \implies y = \frac{3}{4} \] - Substitute \( y \) back to find \( x \): \[ x = 2 + 2(\frac{3}{4}) = 2 + \frac{3}{2} = \frac{7}{2} \] - So the intersection point is \( \left(\frac{7}{2}, \frac{3}{4}\right) \). 4. **Intersection of \( -3x + 2y = 3 \) and \( 6x + 4y = 24 \)**: - Solve \( 6x + 4y = 24 \) for \( y \): \[ 4y = 24 - 6x \implies y = 6 - \frac{3}{2}x \] - Substitute into \( -3x + 2(6 - \frac{3}{2}x) = 3 \): \[ -3x + 12 - 3x = 3 \implies -6x = -9 \implies x = \frac{3}{2} \] - Substitute \( x \) back to find \( y \): \[ y = 6 - \frac{3}{2}(\frac{3}{2}) = 6 - \frac{9}{4} = \frac{15}{4} \] ### Step 4: Identify feasible region Plot the points \( (4, 0) \), \( \left(\frac{7}{2}, \frac{3}{4}\right) \), and \( \left(\frac{3}{2}, \frac{15}{4}\right) \) on the graph to identify the feasible region. ### Step 5: Evaluate the objective function at the vertices 1. At \( (4, 0) \): \[ Z = 5(4) + 2(0) = 20 \] 2. At \( \left(\frac{7}{2}, \frac{3}{4}\right) \): \[ Z = 5\left(\frac{7}{2}\right) + 2\left(\frac{3}{4}\right) = \frac{35}{2} + \frac{3}{2} = \frac{38}{2} = 19 \] 3. At \( \left(\frac{3}{2}, \frac{15}{4}\right) \): \[ Z = 5\left(\frac{3}{2}\right) + 2\left(\frac{15}{4}\right) = \frac{15}{2} + \frac{30}{4} = \frac{15}{2} + \frac{15}{2} = 15 \] ### Step 6: Determine maximum and minimum values - Maximum value of \( Z \) is \( 20 \) at \( (4, 0) \). - Minimum value of \( Z \) is \( 15 \) at \( \left(\frac{3}{2}, \frac{15}{4}\right) \). ### Final Answer: - Maximum value: \( 20 \) - Minimum value: \( 15 \)
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