why is this sentence "she has gone for hours" wrong?

[falling slowly]

A friend of mine asked me that why "she has gone for hours" is not right.
Instead, text book says 'she has been gone for hours" is correct.

Does anybody know the difference between them?

thanks in advance!

[Coli]

It is quite simple...She has been gone for hours. Means that the person has been absent for hours. (Present Perfect - passive). From the past until now, f.ex. she left in the morning and still didn't return home.
She has gone for hours - Present Perfect. - active, would mean that she went for hours. Like in the sentence: She has gone to the supermarket.

I hope you can notice the difference.