some math questions from GMAT summer test, mock

lindazhou

Q1, if N is a possitive integer and R is the remainder when (N-1)(N+1) is divided by 24, what is the value of R?

1)     N is not divided by 2

2)     N is not divided by 3

lindazhou

Q2, if Z的n次方=1, what is the value of Z?

1)N is a nonzero integer

2) Z>0

lindazhou

Q3, if x>Y^2>Z^4, which of the following statements could be true?

1, x>Y>Z

2, Z>Y>X

3, X>Z>Y

Key: 1,2,3

lindazhou

Q4, each employee on a certain task force is either a manager or a director, what percent of the employees on the task force are directors?

1)     the average (arithmetic mean ) of salary of the managers on the task force is $5,000 less than the average salary of all employees on the task force.

2)     The average (arithmetic mean0 salary of the directors on the task force is $15,000 greater than the average salary of all employees on the task force.

Key: C

lindazhou

Q5, a certain city with a population of 132,000 is to be divided into 11 voting districts, and no district is to have a population that is more than  10 percent greater than the population of any other district, what is the minimum possible population that the least populated district could have?

Key :11,000

lindazhou

Q6, a set of 15 different integers has a median of 25 and a range of 25, what is the greatest possible integer that could be in this set?

Key: 43

lindazhou

Q7, if the terms of a sequence are t1,t2,t3,……tn, what is the value of n?

1)     the sum of the n term is 3,124

2)     the average (arithmeticmean) of the n terms is 4

key: C

lindazhou

ding

nickt

1)C R=0 (找个数代一下,7,11)////或者24=3*2*2*2 由1)=>N为odd.(N-1)(N+1)为两偶数相乘,可消除24里的2个2.    由2)=>N不为3整除,则(N+1)(N-1)中必有1可为3整除,有1偶数,24可消去一个2,一个3.(1)+(2)得n为不可被3整除的奇数:24可被消除.所以R=0

2)C  :1)=> N可能为正,负1 .2)=>排除-1

3)1,2,3 对3)X ,Y,Z可以取99/100,1/2,3/5

4)没办法,我选E

5)11000,设最少为X,则(1.1*X*10)+X=13200

6)43  ......25......假设按顺序排列,要使最大,则数列中25前的数字必须最小.(排除25前有负数,因为25-负数,则超出range25).所以前面是第一个25-7=18,18+25(range)=43

7)C   Sum=N*Ave

lindazhou

thanks