In a lucky draw, Mary wins a free air ticket to Australia which can be sold for $8000. Does Mary's cost of using the air ticket change if the price of the air ticket drops to $6000? WHY?
THANKS =D
收錄日期: 2021-04-13 15:53:20
原文連結 [永久失效]:
https://hk.answers.yahoo.com/question/index?qid=20080729000051KK02694