Although repeating "to" twice might be preferred by most English grammar style guides, and be less ambiguous, "to clean and sweep" generally implies the "to" will make both verbs infinitives, and it's highly unlikely that someone knows "safisha" is an infinitive but not "fagia" anyway. In addition, many translations give room for the users to make mistakes anyway (most notably between singular and plural forms of "you") and this is relatively minor in comparison. Thus, I propose that "to clean and sweep" (and "to sweep and clean") be accepted as answers. (I have submitted a report) Does anyone disagree? I would be interested to hear your opinion.
Here are some links discussing this grammatical issue: https://english.stackexchange.com/questions/277044/using-a-to-infinitive-after-coordinating-conjunctions-e-g-and-or-not?rq=1
It depends on the context of the English sentence for me. If I say "I want to clean and (to) sweep the garage today," for example, the second "to" is really unnatural and I'd drop it. If it's just on its own though, or when discussing two verbs, eg. "I learnt the verbs 'to clean' and 'to sweep'", then I'd use "to" with both.
... and this is, in my opinion, the worst thing about this course - worse than all of the errors in the answers and missing answers - there are so many completely contextless exercises such as this one. If they just put Ninataka at the beginning and maybe an object at the end, we'd have a nice sentence and we'd also be practicing more words constantly instead of just learning a word on its own once and never using it in a sentence.