Fourth graph.
Step-by-step explanation:
Using demos calculator we plot the graph.
Orange Shaded area shows the equation : ![x + y\leq 50](/tpl/images/0249/4426/fd0ae.png)
Blue area shows the equation: ![x\geq 20](/tpl/images/0249/4426/9ed95.png)
Refer the attached image
The solution of the equations is (20,30) and (50,0)
The fourth graph shows the same solutions.
So, Graph 4 is correct.
Hence fourth graph represents the solution to the system of inequalities.
![Which graph represents the solution to the system of inequalities? x + y ≤ 50 x ≥ 20](/tpl/images/0249/4426/ba279.jpg)