What discount would Mr. Yang offer?

Woman: Mr. rang, your price for color TV set is too high.
Man: Well, Mr. Smith, I don’t think so, because we offered you CIF Washington.
Woman: Your price is not competitive at all, compared with that in the international market.
Man: You know, our prices mainly depend on the size of your order. Could you tell me how much you want to order?
Woman: Five thousand.
Man: We’ll give you a 10 percent discount.
Woman: It’s too low a rate compared with those we get from other suppliers, I’m afraid.
Man: What’s your counter-offer then?
Woman: To have this business concluded, you need to lower your price at least by 20 percent, I believe.
Man: Then, we meet half way. What about 15 percent?
Woman: Good. Let’s call it a deal.