"To join profit and pleasure"

This morning an E.E. II student asked me how to say "unir/juntar o útil ao agradável" in English, and I just couldn't remember.  I remember telling her that the expression wasn't translated literally -- not at least as far as the usage of the preposition ("a") goes in the Portuguese expression because of the verb ("unir algo 'a' algo"), and also, of course, that both Portuguese words "útil" and "agradável" cannot be translated (again, at least not literally) as "profit" and "pleasure".  So, here it goes: "unir/juntar o útil ao agradável" in Portuguese is the equalivalent to "to join profit and pleasure" in English.  I remembered how to say it this morning as I was driving back home from UFPI after classes.  Sometimes I think I'm just getting old when I can't remember certain things, such as this very common expression in English!