Translation:Is Friday the fifth or the sixth day of the week?
To include the second "the" seems hypercorrect to me, not what is most commonly heard or used.
And wht is the answer? When does a week begin? Sunday or Monday? Here in Europe it's Monday, therefore Friday is the fifth day. But how is it in other countries? In Greek the names of the days derive from a system, where the first day is Sunday. Therefore the name for Monday means "second day" and so on. Πέμπτη (pémpti), literally the fifth day, is Thursday! Very confusing! Because I know Greek very well I translated pátek wrongly with Thursday.