How to calculate the price rating of a product?

Question

Mathematics

We need a formula.
There are a number of products ranging from 30,000 to 200,000. And a certain product worth 70,000. You need to assign a value to it based on the price.
Given:
Min. item price = a
Max. item price = b
Item price = c
Question:
How to get the item price rating if the minimum rating is 5 for the maximum price and 10 for the minimum price.

Answer 1

This is called interpolation. You know that f(a)=10, f(b)=5. You need to find f(c), where f must fall under common sense (a monotonous, continuous function).
for example, you can take a linear interpolation, then f(x) = 10-(xa)/(ba)*5.