Answer: 2.50 dollars
Explanation:
Locate 5 on the x axis, which corresponds to buying 5 kgs of apples.
Draw a vertical line through 5 on the x axis until you reach the blue line. Mark this as point P.
From point P, draw a horizontal line until you reach the y axis. You should arrive at y = 2.5
This tells us that buying x = 5 kgs of apples will cost a total of y = 2.50 dollars.