ChaseDream
搜索
返回列表 发新帖
查看: 765|回复: 1
打印 上一主题 下一主题

请教一道陈向东的数学题

[复制链接]
跳转到指定楼层
楼主
发表于 2009-12-11 21:55:46 | 只看该作者 回帖奖励 |倒序浏览 |阅读模式
a home owner must pick between paint A,which costs 6 per liter, and paint B,which costs 4.5 per liter. Paint B takes one-third longer to apply than paint A.If the homeowner must pay the cost of labor at the rate of 36 per hour,which is the two paints will be cheaper to apply?
(1) the ratio of the area covered by one liter of paint A to the area covered by paint B is 4:3.
(2)pait Awill require 40 liters of paint and 100 hours of labor.
这题的答案是E,我怎么觉得是A啊。设A要x liters,h hours
那么A的成本就是6x+36h
B的成本是4.5x*4/3+36h*4/3=6x+36h*4/3
显然A比B便宜啊。

大家告诉我是我错了还是答案错了。
谢谢了!
收藏收藏 收藏收藏
沙发
 楼主| 发表于 2009-12-11 22:13:31 | 只看该作者

自己顶一下

怎么没人帮我回答下呢
您需要登录后才可以回帖 登录 | 立即注册

Mark一下! 看一下! 顶楼主! 感谢分享! 快速回复:

手机版|ChaseDream|GMT+8, 2024-12-2 21:32
京公网安备11010202008513号 京ICP证101109号 京ICP备12012021号

ChaseDream 论坛

© 2003-2023 ChaseDream.com. All Rights Reserved.

返回顶部