求助 数学PP(DS)-50

lucy1006

50. 4230-!-item-!-187;#058&003784
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.
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【答案】C

谁能解释这个题目呢？！ 感谢万分~

flyzoe小猪

我设m的成本为A那么根据条件1，我知道总成是3A，和L的成本为2A，而总投资是5×10^5,我算出L大约是3×10^5.
根据条件2我了解p》2A，即》3×10^5>1.5*10^5

cuteyb

由题目知：p=500,000-M-L
(1) The company's total cost was three times its cost for materials.
     得 L=2C/3 ，但不知道具体数字
(2)The company's profit was greater than its cost for labor.
    P>L  单独看 条件也不够

1+2 得出 500，000=P+M+L=P+C>L+C=5C/3  得出C<300,000  ，所以P>200,000 P>150,000