The minimum value of $Z=3x+5y$ subject to constraints 

$x+3y\ge 3$

$x+y\ge 2$

$x,y\ge 0$ is  

Solve the following linear programming problem:

Maximise: $Z=3x+4y$

subject to the constraints $x+y\le 4,x\ge 0,y\ge 0$

Solve the following linear programming problem graphically:

Maximise $Z= 4x+y$

Subject to the constraints $x+y\le 50$

$3x+y\le 90$

$x\ge 0, y\ge 0$