求助 官方prep 1一道DS题不解

才谷BC

答案选的是A，为啥？？不应该1）和2）都可以推出Spanish Manchego的价格吗？

A gourmet cheese shop sold several orders of English Stilton and Spanish Manchego yesterday. Customer A purchased 15 pounds of English Stilton and 3.75 pounds of Spanish Manchego for a total of $438.00. If the price for each of these cheeses is proportional to its weight, what is the price of 1 pound of Spanish Manchego?

(1) Customer B purchased 5 pounds of English Stilton and 4 pounds of Spanish Manchego for a total of $214.75.

(2) Customer C purchased 6 pounds of English Stilton and 1.5 pounds of Spanish Manchego for a total of $175.20.

才谷BC

自问自答 - 后来研究了下发现，2）的公式里面，比例和题干是一模一样的，所以无法解出这个二元一次方程

Ratikainen

这个把戏已经被GMAC用烂了。基本给这种两个相似的二元一次方程立马就要警觉是个陷阱，写下来算一算就OK。