Answer with explanation:
Cost of a Pencil = $ 0.25
Cost of a Eraser = $ 0.50
⇒Total Amount Spent on Pencil and Eraser < 3.
⇒Cost of x Pencil +Cost of y Eraser < 3
⇒ 0.25 x + 0.50 y < 3

⇒Put, x=0 and y=0,to know which side of the graph you have to shade.
0+0< 12⇒0< 12
Shade that part under line, which contains origin.