The answer to the given question above would be option A. Based on the given map shown above which is a typical flight path between Seattle and London, the reason why the path goes over the Arctic is that, it is the shortest path. Hope this answers your question.
If Lee downloaded 3 more songs than Howard (16 total songs), that means that Howard downloaded 13 songs (total). If Howard downloaded 13 songs, he downloaded 6 more than Erin. Therefore, you would subtract 6 from 13 to get 7.