Question: how to find the constant of proportionality in a word problem?
Answer: To find the constant of proportionality, we use the formula k=y/x. So we have k=20/500 = 0.04. The equation representing this situation will look like y=kx. Substituting in our value of k that we found, we have the equation y=0.04x. We can use our equation to find the answer to this problem.