Answer:
8000,I think this is right answer
Hope these help but i wrote all of it out with all its geometrical reasons
If a graph is proportional then the line will go through the origin at point (0, 0). If the equation is proportional then it will be in the form of y=kx with no other operations after. The constant of proportionality is another way to say the slope and in your specific equation the slope would be 1/5.
The answer is 5/1 because reciprocal means to flip a fraction.