I am currently mentoring my little brother in mathematics. There is an issue with the pedagogy of unit rates. For example when given the following concept " 11.00 U.S. Dollars to 20 Planet X Dollars Find the Unit Exchange Rate." I am aware that does eventually leads to unit rates which is the name of the lesson the math teacher is on. Which the individual has also explained. The issue is are there any resources on how to understand the unit rate, cost, or etc. that is being presented in this lesson outline? My attempts to help him with problem has been to grasp that the problem ultimately has to do with something like this $\frac{\mathrm{rate}}{1}=\frac{11.00}{20}$. Or are there any examples, or methods that can help drive the concept home?
Edit
This is arbitrary " 11.00 U.S. Dollars to 20 Planet X Dollars Find the Unit Exchange Rate." Any rate either from U.S dollars to Planet X dollars or reverse is fine. Here is the specific one "11.00 U.S Dollars to 20 Planet X Dollars Find the Unit Rate Exchange for U.S Dollars to Planet X Dollars." Again none of these specific problems are actually meaningful if the general concept is what is the underlying issue. Firstly, the definition of ratio, proportion, fraction, and decimal are all given before hand if the assessment of these problems are being presented. This is a stack exchange about Math Educators so math educators in the domain of middle/elementary school would ideally know the issue. The Unit Rate might not make a lot of sense it college educator level, but it does to me a student who passed Calculus 1, 2, 3, and Differential Equations and is aiming to major in Mathematics, and finds uses to its applications.