This happens to me all the time on Ask Ubuntu:
Question from JB: How do I accomplish exactly X on my machine?
 Answer by AZ: Here's a tutorial showing you exactly how and even more useful related stuff.
 Answer by AZ: Here's a clear general answer for which your answer is an example; still written clearly enough that it's obvious how to answer your question, though.
 Answer by JB: This is just me using the knowledge AZ gave me to write out explicitly the precise answer to my original question.
Who do I upvote? Who gets a checkmark?
I intuitively want / to get the checkmark, but  is the exact answer that somebody would want to find on a quick search. I'd like to give upvotes to both anyway. But who cares what I want? What's the right thing to do?