Questions and answers in textbooks that don't make sense

[Valda]

These sentences are from a textbook 

Q: Est-ce que vous vendez des legumes?
A: Non, je ne vends que des fruits

Q: Est-ce que vous vendez des fruits?
A: Non, je ne vends que des legumes.

I don't understand why the answer to the question "Do you sell vegetables?" should be "No, I don't sell fruits". And the answer to the question "Do you sell fruits" should be "No, I don't sell vegetables."

Shouldn't it be the other way around ?

[Chantal Savignat]

Hello.

"Est-ce que vous vendez des légumes ?" = "Do you sell vegetables ?"   : it's right

But "Non, je ne vends que des fruits" is not a negative form even if there is the word "ne" because of the word "que"

"ne ....(verb) ... que"  = "seulement" = "only"

So for your sentence :

"Non" is the answer

and there is an additional information "Je ne vends que des fruits" = "je vends seulement des fruits" = "I only sell fruits"

it's the same thing for the second sentence.

[Valda]

Salut!

Maintenant je tout comprends :) Merci! 

[Chantal Savignat]

just a little correction if you want :

Maintenant je tout comprends => it's "Maintenant je comprends tout"

in French these small words (pronouns, adverbs ...) are generally after the verb.

(I have exactly the same problem in English :-) )