If $\mathrm{Z}=7 x+y$ subject to $5 x+y \geq 5, x+y \geq 3, x \geq 0, y \geq 0$, then minimum value of…

If $\mathrm{Z}=7 x+y$ subject to $5 x+y \geq 5, x+y \geq 3, x \geq 0, y \geq 0$, then minimum value of $\mathrm{Z}$ is
  1. 2
  2. 5
  3. 6
  4. 3

Solution

Feasible area is shaded. Point of intersection of given lines is $\mathrm{P} \equiv\left(\frac{1}{2}, \frac{5}{2}\right)$ Co-ordinates of points are as follows : $C \equiv(3,0) ; P \equiv\left(\frac{1}{2}, \frac{5}{2}\right)$ and $B \equiv(0,5)$ We have $Z=7 x+y$ $Z_{(c)}=21+0=21$ $\therefore \quad Z_{(B)}=0+5=5$ $Z_{(P)}=\frac{7}{2}+\frac{5}{2}=6$ Thus minimum value is 5.

Asked in: MHT CET 2020 (12 Oct Shift 1)

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