I think what the above implies is that as long as a user owns a file, the user’s group also owns that file. Therefore, any user that is a member of that particular group is also seen as an owner of that file and all files owned by that group as well. Therefore, the group permission would apply if the current user is a member of that group but not the owner of the file.
If the user is the owner of the file, then owner permissions are applied and if the user is neither the owner nor a member of the owner’s group then the ‘others’ permission applies.
What this is saying is that as the owner of the file, user permissions would apply when learn handles the file. But for dq’s case, user permissions don’t apply. If dq is a member of learn’s group (which we don’t know) then group permissions would apply for questions 3 & 4, else ‘others’ permission would apply. I think both group and ‘others’ permissions were set to the same thing so that we can arrive at the same correct answers irrespective of whether dq is a member of learn’s group or not.