Two products with substantially different prices may be in the same market if consumers make a price-quality trade off. On the other hand, one could argue that an LPG customer paying a 100 per cent premium over the price of a product that performs the same function as LPG would be unlikely to respond to a 5
per cent change in the relative price (which would increase the premium by around 10 per cent).
參考答案:如果消费者对商品的价格和质量做充分考虑，那么在一个市场中可能存在价格相差很多的同种商品。
另一方面，有些人认为，假如一个准备购买液化气的客户能买到一种与液化气有同等功效，但价格便宜100%的产品，那么这个客户就可能对液化气的价格变动5%无动于衷。液化气价格将继续下降10%。