请教陈向东数学上的一道题

ceciliazlh

A home owner must pick between paint A, which costs $6.00 per liter, and paint B, which costs $4.50 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 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 one liter of paint B is 4:3.

2> Paint A will require 40 liters of paint and 100 hours of labor.

这道题答案是E。我选的C，因为我大概算了一下，用1和2的条件是可以算出用A和B涂房子各需要多少钱。不知道有哪位高手能帮我解答一下为什么答案是E? 谢谢。

ceciliazlh

没有人做过这道题吗？