I strongly suspect there were both word problems used in your math classes and that compound interest was in the curriculum. But maybe there is somewhere there actually isn't. Generally, the curriculum documents are all publicly available online too so feel free to take a look. Although finding the curriculum from 10+ years ago can be hard if there have been changes.
Had you really never seen something like 'Joe currently owes $300 on his credit card with an annual interest rate of 22%. How much will he owe 2 years from now if he makes no payments and no new purchases'?
All you need is the compound interest formula. It could be about investments or a ball accelerating due to gravity and it's still just that same formula with different numbers plugged in.