JAMIA 2023 — Mathematics PYQ
JAMIA | Mathematics | 2023Z=7x+y, subject to constraints:
5𝑥+𝑦≥5,
𝑥+𝑦≥3
𝑥≥0,𝑦≥0,𝑦
Then minimum value of Z occurs at:
Choose the correct answer:
- A.
(0,5)
(Correct Answer) - B.
(3,0)
- C.
(7,0)
- D.
(1/2,5/2)
(0,5)
Explanation
1. Objective Function and Constraints
-
Minimize: Z=7x+y
-
Constraints:
-
5x+y≥5
-
x+y≥3
-
x≥0,y≥0
-
2. Identify Boundary Lines and Intersections
We find the intersection points of the boundary lines with the axes and with each other.
Line L1:5x+y=5
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When x=0, y=5⟹(0,5)
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When y=0, x=1⟹(1,0)
Line L2:x+y=3
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When x=0, y=3⟹(0,3)
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When y=0, x=3⟹(3,0)
Intersection of L1 and L2:
Solve the system:
-
5x+y=5
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x+y=3⟹y=3−x
Substitute y in the first equation:
Intersection point: (21,25) or (0.5,2.5).
3. Determine the Feasible Region Corner Points
The constraints are "greater than or equal to," so the feasible region is unbounded and lies above the lines. We test the points to see which ones bound the feasible region:
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(0,5): Satisfies both 5x+y≥5 and x+y≥3.
-
(21,25): Satisfies both (intersection point).
-
(3,0): Satisfies both 5x+y≥5 and x+y≥3.
The corner points are: (0,5), (0.5,2.5), and (3,0).
4. Calculate Z at Corner Points
We substitute the corner points into Z=7x+y:
-
At (0,5):
Z=7(0)+5=5 -
At (0.5,2.5):
Z=7(0.5)+2.5=3.5+2.5=6 -
At (3,0):
Z=7(3)+0=21
5. Final Answer
Comparing the values 5,6, and 21, the minimum value is 5.
Result:
The minimum value of Z occurs at:

