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Consider an LPP: Maximise Z=50x+15yZ = 50x + 15y subjected to constraints

x+y≤60x + y \leq 60,

5x+y≤1005x + y \leq 100,

x,y≥0x, y \geq 0.

If the maximum value of ZZ occurs at x=αx = \alpha and y=βy = \beta, then the value of α+β\alpha + \beta is

Solution

✅ Correct Option: 2

In any LPP, the maximum or minimum value occurs at a corner point of the feasible region.

The corner points are:

Origin: (0,0)(0, 0)

Where 5x+y=1005x + y = 100 meets the x-axis, set y=0y = 0:

5x=1005x = 100

x=20x = 20

Point: (20,0)(20, 0)

Where x+y=60x + y = 60 meets the y-axis, set x=0x = 0:

y=60y = 60

Point: (0,60)(0, 60)


Intersection of the two lines:

x+y=60x + y = 60 ... (1)

5x+y=1005x + y = 100 ... (2)

Subtracting (1) from (2):

(5x+y)−(x+y)=100−60(5x + y) - (x + y) = 100 - 60

4x=404x = 40

x=10x = 10

Substituting x=10x = 10 in equation (1):

10+y=6010 + y = 60

y=50y = 50

Point: (10,50)(10, 50)


Evaluating Z=50x+15yZ = 50x + 15y at each corner point:

At (0,0)(0, 0): Z=50(0)+15(0)=0Z = 50(0) + 15(0) = 0

At (20,0)(20, 0): Z=50(20)+15(0)=1000Z = 50(20) + 15(0) = 1000

At (0,60)(0, 60): Z=50(0)+15(60)=900Z = 50(0) + 15(60) = 900

At (10,50)(10, 50): Z=50(10)+15(50)=500+750=1250Z = 50(10) + 15(50) = 500 + 750 = 1250


The maximum value of ZZ is 12501250 at point (10,50)(10, 50).

Therefore, α=10\alpha = 10 and β=50\beta = 50

α+β=10+50=60\alpha + \beta = 10 + 50 = 60

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