Learn Italian: L'imprenditore con il quale lavoro cerca di risolvere il problema attuale. - The entrepreneur with whom I work tries to solve the current problem.

You can absolutely say con cui, which is very common in everyday speech! Using il quale (and its forms la quale, i quali, le quali) after a preposition is a slightly more formal alternative. Because it includes the article il, it has to match the gender and number of the noun it refers to—in this case, the masculine singular l'imprenditore.

Wait, doesn't attuale mean "actual"?

This is a classic "false friend." Attuale actually means "current" or "present" (related to the present time). If you want to say "actual" in the sense of "real," you would use words like vero or reale.

Why is the article il used with problema if the word ends in "-a"?

Problema is one of those tricky exceptions. Many Italian words that end in -ma and come from ancient Greek are masculine, not feminine. Other common examples you might know include il sistema (the system) and il programma (the program).

Why is there a di between cerca and risolvere?