"Good afternoon, László!"
Translation:Jó napot, László!
Since I just learned the word afternoon in Hungarian ("délután"), it doesn't make sense to not accept "jó délutánt, László" as an answer. "Good day, László" would be the thing to ask if you expect "jó napot, László" as an answer.
It's a good idea, but no one ever says "jó délutánt!". Or "jó délelőttöt!", as a matter of fact. "Good afternoon!" is what roughly corresponds to "jó napot!" (the Hungarian phrase can be used from half past nine / nine, while the English is used from midday.)
Then the exercise should be translate "good day", not "good afternoon". It's not a common phrase in English anyway, but very antiquated. There's not some kind of linguistic void that is left by the exclusion of good afternoon. English speakers aren't going to toss in turn in their beds at night because they don't know how to say "good afternoon". It's like suggesting the Hungarian for "jerked chicken" is really "csirkes paprikas" because no one eats jerked chicken in Hungary: jerked chicken is not so fundamental to our understanding of the language that it is necessary to misconstrue its meaning.
"Good day" is simply just not used in everyday life, "good afternoon" is. (Note: I wouldn't see it as a problem the other way around.)
"Good afternoon" is used after "good morning" but before "good evening", just like "jó napot" is used after "jó reggelt" but before "jó estét." I don't think many people would attack translating "jó reggelt" as "good morning" & definitely no one would have a problem with translating "jó estét" as "good evening." "Good afternoon" just fits.
This is how it's usually translated the other way around. At least, when I was learning English in my grammar school, "good afternoon" was the equivalent of "jó napot." If it's not broken, I don't think it needs to be fixed.
I'm not currently doing the Hungarian course, so I can't see the course notes right now. But what it needed here, is to include an explanation about Hungarian greetings if there isn't already one available. Saying when to use which, clarifying what reggel means &c. If there's no such thing, let the creators know, please, if there is, please (again) do read it.
Adding kívánok to the sentence would make it translate more closely to "I wish you good afternoon, László" It has roughly the same meaning, but adding kívánok makes it sound slightly more formal than the English sentence