诚意请教几道数学题！！

juliazhu15 · 发表于 2010-10-19 15:46:49

1. Beginning in January of last year, Carl made deposits of $120 into his account on the 15th of each month for several consecutive months and then made withdrawals of $50 from the account on the 15th of each of the remaining months of last year. There were no other transactions in the account. For May of last year was $2600. What was the range of the monthly closing balance of carl's account last year?(1) Last year the closing balance of carl's account for April was less than $2625.
(2) Last year the closing balance of carl's account for June was less than $2675.

题目的问题我不太明白。“the range of the monthly closing balance”是什么意思？这道题目应该怎么考虑丫？
遇到几次有关“rang”的题目，一直都不太清楚这个在G的数学里是个什么概念，诚请各位指导一下！！

2。 What is the remainder when the positive integer X is divided by 6?
(1) When X is divided by 2, the remainder is 1; and when X is divided by 3, the remainder is 0.
(2) When X is divided by 12, the remainder is 3.
prep上面的题目。这题基本没有任何思路！！
看到N人发的有关求余数的帖子，可是没有讲当除数改变时，怎么解题。
余数题一直让我很抓狂啊！！求救求救！！

3。 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 population district could have?
答案是:11,000
这也是prep上面的一道题目，同样不会解。请教高人指导！！

2010 · 发表于 2010-10-19 16:05:03

1/问CARL去年一年一年帐户里总额的变化范围。其实很简单，就看你能否判断出CARL在哪个月开始变存钱为取钱，画一个时间线，把数据都写上去看，可以看出两个条件都不能单独判断，两个条件一起可以推出MAY是开始取钱的第一个月，这之前都是递增之后都是递减，所以范围就能出来了。 C
2/ 条件1判断可以被三整除的奇数，这样被6除余数肯定是3 ；条件2能被12除余3，那么被6除也肯定余3，12=2*6。
3/ 考虑一种极端情况，要求最小，一定要让最小值偏离均值最远，那么极端情况就是1个最小值，其余全部最大。再根据条件，最大值不超过最小值10%，就可以有
MIN+MIN*110*（11-1）=132000，MIN=11000。

2010 · 发表于 2010-10-19 16:07:32

3/少打了个符号：MIN+MIN*110%*（11-1）=132000，MIN=11000

juliazhu15 · 发表于 2010-10-19 18:01:29

多谢高手，太感谢了！！
能否把第2道题目说得再详细一点？为什么X被12除余3，被6除就一定是余3呢？12=2*6怎么体现？再次感谢！！

诚意请教几道数学题！！

所属分类: GMAT考试

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