The rewards for each question and each answer are separate, with each potentially receiving upvotes that translate into rewards, so there is no "split" as such. 

However, the musing account upvotes typically make up a large percentage of the rewards and they tend to upvote answers more than questions. Over July answers gained an average of $0.22 in rewards and questions $0.04. 

This makes sense as (a) questions are typically easier and shorter and (b) part of the reward for the questioner is receiving all the great answers!