What can be said about the problem: maximise $Z = x + y$ subject to $x + y \le 2$, $x + y \ge 5$, $x \ge 0$, $y \ge 0$?

Explanation

1. 01

   No point can have $x + y$ at most 2 and at least 5 at the same time.

2. 02

   So the feasible region is empty and the problem has no solution at all.