diff --git a/ch15/exercise15_5.h b/ch15/exercise15_5.h
index cb2371b..bf28b2a 100644
--- a/ch15/exercise15_5.h
+++ b/ch15/exercise15_5.h
@@ -10,11 +10,11 @@ class Bulk_quote : public Quote
 		Quote(b, p), min_qty(q), discount(disc)
 	{}
 
-	double net_price(std::size_t n) const override;
+	double net_price(std::size_t n) const override {};
 
 private:
 	std::size_t min_qty = 0;
 	double      discount = 0.0;
 };
 
-#endif // BULK_QUOTE_H
\ No newline at end of file
+#endif // BULK_QUOTE_H