"Fine, and you?"

[Elga726369]

Why not bueno or buena?

[Jay518227]

You can say bueno/buena

For example

Bueno, ¿y tú?
or
Buena, ¿y tú?

Good, and you?

Bien just translates into fine

But both are acceptable

[streamer462]

Because that is wrong.

[DeKomP]

very good ! and you , subtle but different , not a literal translation

[Kitalexi]

Está bien, y usted? - perfect Spanish, and so is "Bien, ¿y tú?". Get it together Duo....

[DiegoXDX]

why not buen?

[Princess298616]

Because that is the wrong spelling the proper spelling is bien