There are 100 glasses arranged in a row.
When I would like someone to pour water into the 3rd glass, the 6th glass, ..., I think I can say
Please pour water into every three glasses or every 3rd glass.
I am trying to generalize this without referring to a specific number (e.g., 3rd ). My example is as follows:
Pour water into every a certain numbers of glasses.
Pour water into every Nth glass, where N is a positive integer.
I would like to allow water to be poured into every glass. Could you advise me on which is better?