GMATprep-【DS】is construction company's profit greater than $150,000 ?

A construction company was paid a total of $500,000 for a construction project. the company's only costs for the project were for labor and materials. Was the company's profit for the project greater than $150,000?

(1) The company's total cost was three times its cost for materials.

(2) the company's profit was greater than its cost for labor.

我的错误答案是E，复习的时候还是没有头绪，到底选什么呢？左算右算，还是陷在里面没有头绪，请大家帮帮忙！

答案是Ｃ

条件一可以得出所有成本＝３＊材料费，另根据题目，所有成本＝劳动力成本＋材料费，那么可以推出劳动力成本＝２＊材料费；

条件二可以得出利润＞劳动力成本，那么利润=500000-所有成本=500000-劳动力成本-材料费〉劳动力成本，结合条件一所得的劳动力成本=2*材料费。可以推出5*材料费〈500000，那么材料费〈100000，所有成本〈300000，可以得出利润肯定大于150000，可以肯定回答问题。

L-Labour M-Materials

From (1), [(L+M)=3M] -> [L=2M]

From (2), [500,000-(L+M)>L] ->[500,000>2L+M] ->[500,000>5M] ->[M<100,000]

Couple (2) with (1), L<200,000

Profit = [500,000 - L - M] > 200,000

I think should choose C.

谢谢楼上的两位朋友！

真是太感谢了！