[求助]GMATPrep math question 1

amacd

DS, in a work force, the empolyees are either managers or directors. What is the percentage of directors?

a) the average salary for manager is $5,000 less than the total average salary

b) the average salary for directors is $15,000 more than the total average salary

answer is C)

i chose E ...

amacd

one more question:

DS: if the integer a and n are greater than 1, and the product of the first 8 positive interger is a multiple of a^n, what is the value of a?

a) a^n = 64

b) n = 6,

answer is b

can someone help to explain the hightlighted part>? thanks alot !!!

ayang1017

以下是引用amacd在2005-10-17 13:50:00的发言：

DS, in a work force, the empolyees are either managers or directors. What is the percentage of directors?

a) the average salary for manager is $5,000 less than the total average salary

b) the average salary for directors is $15,000 more than the total average salary

answer is C)

i chose E ...

正好能算出来，亲手算算其实就知道了

设总的平均数为t，director比例为d%

t*100=(t-500)(100-d)+(t+15000)d

d=4

a-ga

t*100=(t-500)(100-d)+(t+15000)d===>對不起...還是不懂這個式子??

ayang1017

以下是引用amacd在2005-10-17 13:53:00的发言：

one more question:

DS: if the integer a and n are greater than 1, and the product of the first 8 positive interger is a multiple of a^n, what is the value of a?

a) a^n = 64

b) n = 6,

answer is b

can someone help to explain the hightlighted part>? thanks alot !!!

应该说8！是a^n的倍数吧

ayang1017

以下是引用a-ga在2005-10-17 14:44:00的发言：

t*100=(t-500)(100-d)+(t+15000)d===>對不起...還是不懂這個式子??

假设有100个员工，director有d个，manager有100－d个

t平均数，利用总的薪水相等列式子

scrogon

以下是引用ayang1017在2005-10-17 14:39:00的发言：

正好能算出来，亲手算算其实就知道了

设总的平均数为t，director比例为d%

t*100=(t-500)(100-d)+(t+15000)d

d=4

很是厉害，越来越佩服ayang了

scrogon

以下是引用ayang1017在2005-10-17 14:45:00的发言：

应该说8！是a^n的倍数吧

我也没看清楚这句话的意思，这两道题不错，也谢谢楼主

ayang1017

以下是引用scrogon在2005-10-17 14:48:00的发言：

很是厉害，越来越佩服ayang了

有吹捧之嫌～～

一个就要考试的人没事就在在这瞎晃～～～

合适不？

[此贴子已经被作者于2005-10-17 14:52:25编辑过]

amacd

以下是引用ayang1017在2005-10-17 14:45:00的发言：

应该说8！是a^n的倍数吧

thanks alot ayang1017, i didnt expect my problems to be solved in such a short time!! thanks alot

btw -- do u notice that today is 10/17, and you are ayang1017..!!  (your birthday?)

  ^^ thanks again