小弟求教2道prep输血。很多时间不做输血题目了，不行啊。

ss27 · 发表于 2011-11-18 18:01:59

1.The function f is defined for each positive three-digit integer n by f(n) = 2^x 3^y 5^z(2的x次乘以3的y次乘以5的z次）, where x, y, and z are the hundreds, tens, and units digits of n, respectively. If m and v are three-digit positive integers such that f(m) = 9 f(v), then m - v =

A.   8
B.   9
C.   18
D.   20
E.   80

2.To be eligible for retirement benefits at the Omega Corporation, the sum of an employee’s age, in years, and the number of years of employment must be at least 70. If x, where x < 70, is a certain employee’s age when hired and y is the minimum number of years of employment required for the employee to be eligible for retirement benefits, which of the following equations represents the relationship between x and y ?

A.   xy = 70
B.   x + y = 70
C.   2x + y = 70
D.   x + 2y = 70
E.   2x + 2y = 70

多谢各位大牛啦！

huanglel · 发表于 2011-11-18 18:52:21

弱弱的问一下，是不是D, B ？第二题好像我MISS了什么，因为我想的太简单了

ss27 · 发表于 2011-11-18 23:41:16

第二题是d，第一题你可否赐教？

lily2011 · 发表于 2011-11-19 00:05:49

设m=x1y1z1,v=x2y2z2.
根据题意f(m) = 9 f(v)得： 2^x1 3^y1 5^z1= (2^x2 3^y2 5^z2 ) *9
因为9= 3 ^2 所以y1=y2 +2
因为y是十位数，所以是20

ss27 · 发表于 2011-11-20 23:04:54

受教了,多谢!

小弟求教2道prep输血。很多时间不做输血题目了，不行啊。

所属分类: GMAT考试

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