In a perfectly competitive market where fuel is the sole input used, if the price of fuel remains constant but efficiency is doubled, the effective price of travel would be halved (twice as much travel can be purchased).
在完全竞争的市场中，燃料是唯一的投入，如果燃料价格保持恒定但效率翻了一番，旅行的有效价格将减半（可以购买的旅行的两倍）。