Question

DO NOT ANSWER IF YOU DO NOT KNOW

Answer 1

Answer:

By saying "paying the same rate"

I believe you want to know for example when two people are buying a product how to know if they are paying the same amount.

If so then there are a couple of factors at play.

First of all you need to identify the GDP of the product and the amount of tax/VAT which if calculated properly may help you tell if they are paying the same amount or not.