I am a little confused by this sentence. Is it supposed to mean "she writes in ten newspapers" - as in she writes for 10 newspapers.
Or "she writes [in] to ten newspapers", as in she writes a letter to ten newspapers?
I think the sentence is supposed to mean "she writes for 10 newspapers", we might need to look into that one and fix it. Thank you for your comment. ^.^
Could we say "αυτή γράφει για δέκα εφημερίδες" ? Why is σε used here instead of για?