求指教~

zhuyajie · 发表于 2010-8-4 13:37:51

一道数学题 prep中的求指教~
the rate of a certain reaction is directly proportional to the square of the concentration of chemical A present and inversely proportional to the concerntration of chemical B present. If the concentration of chemical B is increased by 100%, which is closet to the percent change in the concentration of chemical A required to keep the reaction rate unchanged?
答案是40% increase

请牛牛指教解题过程~

trandee · 发表于 2010-8-4 16:09:12

rate=A^2/B
=(1.4A)^2/(2B)

分母乘以了2
分子也要乘以2=》根号2=1.4...
所以增长0.4

（我是根据答案倒推的：p）

zhuyajie · 发表于 2010-8-4 20:14:59

谢谢楼上的牛牛~ 醍醐灌顶~

求指教~

所属分类: GMAT考试

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