Translation:The man runs ten kilometers a day.
is per a time unit, such as per day, per week, per month and so on all expressed with accusative/αιτιατική?
Thanks and what about other ratio measurements, such as "miles/hour", "liters/100 kilometer" and etc.?
Miles/hour=Μίλια την ώρα, μίλια ανά ώρα
"Per" in Greek is "ανά", so 1 liter/100 km= ένα λίτρο ανά 100 χιλιόμετρα
it still shows 'the' and not 'a'. but in any case why is the indefinite article not used here in Greek.
Due to the method of writing hints for various sentences often containing the same word e.g. "την" as here sometimes even though it has been changed it reverts when it is repeated in another sentence. In any case, I think I got it now by adding "kilometers a day" as a phrase which has less chance of changing.
I don't know what the distinction would be but I think you could say "each day" or "every day"
"Each day" would be used if there were specific days involved. "Each day it doesn't rain". e.g.