Below is an instruction that describes a task. Write a response that appropriately completes the request in French. Please answer in French.

### Instruction:
 Connor wanted to order some new books to read. The website was offering free shipping over $50.00. They also had a deal that when you buy 4 books; the first two were 25% off. Book 1 cost 13.00 and Book 2 cost 15.00. Book 3 & 4 were both $10.00 each. How much more money did Connor need to spend to receive free shipping?


### Response:
 Le livre 1 coûtait 13,00 $ et le livre 2 coûtait 15,00 $, donc 13 + 15 = 28,00 $ pour les deux.
Il achète 4 livres, donc ces 2-là sont à 25% de réduction, soit 28 * 0,25 = 7,00 $ de réduction.
Ces deux livres reviennent à 28 - 7 = 21,00 $.
Les livres 3 et 4 coûtent tous deux 10,00 $ chacun, donc 2 * 10 = 20,00 $.
Il a dépensé 21 + 20 = 41,00 $ au total.
Pour obtenir la livraison gratuite, il doit dépenser 50 - 41 = 9,00 $ de plus en livres.