In English, the choice between "a" and "an" is determined by the that immediately follows the article, not the spelling.
: "Eleven" starts with a vowel sound (/ɪˈlɛvən/). 11093.rar
: Because the first sound is a vowel, you must use " an " (e.g., " I downloaded an 11093.rar file "). Contextual Usage In English, the choice between "a" and "an"