I'm a fair newbie on Stack, and the whole duplicate question thing has always left me a bit confused, as like @Mukesh Sai Kumar I've consistently found better answers on the duplicates than on the original question.
This whole issue really leaves me with the question :) of:
When the duplicate question is marked duplicate, why aren't the duplicate answers automatically just moved to the original question and the duplicate's URL then auto-redirects to the original question?
When the duplicate question is marked duplicate, why aren't the duplicate answers automatically just moved to the original question and the duplicate's URL then auto-redirects to the original question?
Something like that would ‘fix’ the “Where’s the best answer?” problem.
Now back to Mukesh's question...
Do good quality answers on duplicate questions deserve reputation?
Yes! The key is 'good quality.' Any good quality question, or answer, deserves positive reputation.