The main clause "Few people knew the answer" implies a negative meaning, as "few" suggests not many people knew (കാരണം "few/കുറച്ച്" ആളുകൾക്ക് അറിയില്ലെന്ന് സൂചിപ്പിക്കുന്നു)
The rule for forming question tags is that if the main clause is negative, the tag should be positive.
"Knew" is in the past tense, so the tag should use "did" to match the tense.
