PREP1上的一道数学题。。。没看懂题。。求助

cptbtptp · 发表于 2011-12-19 12:42:43

When a certain tree was first planted, it was 4 feet tall, and the height of the tree increased by a constant amount each year for the next 6 years. At the end of the 6th year, the tree was 1/5 taller than it was at the end of the 4th year. By how many feet did the height of the tree increase each year?

(A) 3/10
(B) 2/5
(C) 1/2
(D) 2/3
(E) 6/5

说and the height of the tree increased by a constant amount each year for the next 6 years 到底是怎么的啊答貌似是选D 我忘了 == 模考的时候做到的，不会做

avalon9527 · 发表于 2011-12-19 23:46:19

一棵树开始高4 feet，每年都长高一个固定值。第6年底，它比第4年底要高出1/5。问每年它长多少？
设每年长x feet，那么4年后高度就是 4+4x， 6年后高度是4+6x。方程为 (4+6x)/(4+4x)=6/5
最后得出x=2/3

PREP1上的一道数学题。。。没看懂题。。求助

所属分类: GMAT考试

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