Duplicate suggestion above

If it requires a hint, so do all other katas.

Indeed, especially

The major complication is the value of both cars is decreasing (i.e. depreciating). They both decrease by the same percent per month, 1.5% for our first test. Additionally, the amount of depreciation increases by 0.5 percent every second month.

is WAY more accurate. I'm filing an issue because "Furthermore the percent of loss" clearly implies that it only goes for the depreciation of the OLD car, not the new (that's a WIN, not a LOSS)

Not an issue.

codewars uses its own testing framework that's only vaguely related to how testing works in different languages

You're meant to return the value as a Bool and not a string. Remove the quotation marks and capitalise them.

Boolean values have a signicant meaning and cannot be represented in strings in order to make them work. This is similar to numbers in programming: "5" and 5 are completely different things and are examples of polymorphism.

Hard to determine without seeing your code - post it as a reply to this comment and I can have a look for you.