请教一道数学题（陈向东数学）

dan0909

陈向东数学第四篇-142题

A home owner must pick between paint A, which costs 6 USD per liter, and paint B, which costs 4.5 USD per liter. Paint B takes one-third longer to apply than paint A. If the home owner must pay the cost of labor at the rate of 36 USD per hour, which of 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) Paint A will request 40 liters of paint and 100 hour of labor.

答案是E。
但我觉得应该是C，通过（1）+（2），既可以知道A、B各用多少升，又可以知道A、B各需要多少小时labor。油漆和Labor的单价都有，就可以比较了。

麻烦帮忙看看我的思路哪里有问题？
谢谢！！！

dan0909

各位，谁帮忙指点一下，谢谢！

yangwq2006

我怎么觉得是A。。。Paint A cost 6, covers 4; Paint B cost 4.5, covers 3，说明每平米面积的成本都是一样的。PaintB需要的时间长，人工费贵，总价也贵。。。