PP-T1-DS50

[slin0717]

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.

答案:C

能請版上的先進指點一下嗎?謝謝

[amyliang]

based on the question, C=L+M, Pro=Rev-Cost=Pro=500k-(L+M)
(1)C=3M=M+L => Pro=500k-3M insufficient
(2)P=R-C>L => Pro=500k-C>L insufficient

(1)+(2)
P=500k-C=500K-3M>L (L=2M)
M<100
P=500k-3M=200 which is greater than 150K

[slin0717]

謝謝...

[chencraig0227]

based on the question, C=L+M, Pro=Rev-Cost=Pro=500k-(L+M)
(1)C=3M=M+L => Pro=500k-3M insufficient
(2)P=R-C>L => Pro=500k-C>L insufficient

(1)+(2)
P=500k-C=500K-3M>L (L=2M)
M<100
P=500k-3M=200 which is greater than 150K

請問 M<100, 又L=2M, 所以 L<200吧! 怎麼會直接導出P=...=200?

[canadacom_orig]

應該是p>200...

他只是把p最小的可能寫出來

p最小趨近於200 但大於200

[chencraig0227]

應該是p>200...

他只是把p最小的可能寫出來

p最小趨近於200 但大於200

不好意思! 這邊我轉不出來...
M<100 所以 2M<200
那麼P<L, L=2M 所以 P<2M (2M<200)
這樣P應該要<200阿? 怎麼會大於呢??

[larry.tw]

弄簡單一點給你參考參考

(2)其實應該是 P>L (profit > Labor cost)
(1) + (2)
P > L
=>500-3M > L
=>500-3M >2M
=>5M < 500
=> M<100

又P=500-3M
把M<100代進上面的式子(隨便代99,98)應該很容易看出來,p永遠大於200,充分

看到你的問題了!!!不是P<L喔 ^^""

[chencraig0227]

感激! 做數學腦子真的容易打結!