og12数学161，求解呀

腹黑男

这道题我研究了半天也不知道究竟怎么做，各位大侠给个思路说明吧

161. 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 last year. If the
closing balance of Carl’s account for May of last year
was $2,600, what was the range of the monthly
closing balances of Carl’s account last year?


(1) Last year the closing balance of Carl’s account
for April was less than $2,625.
(2) Last year the closing balance of Carl’s account
for June was less than $2,675.


小弟跪谢大家啦

Tobelogical

假设不带利率
1和2合起来说明5月是转折点，开始往外拿钱
初始余额为a，可以算出是2000，那么也就知道了

如果带利率
也能说明5月是转折点，未知数是利率和初始余额，哥就糊涂。。。

如果利率算是已知数的话，选C

garlicwu

OG 上解释了，不考虑利息，“no other transactions in the account last year”

更正一下，翻译OG上的解释：
条件1只能说明5月还是存钱的，以后存不存不知道
条件2只能说明6月是取钱的，以前取不取不知道

合起来根据5月closing balance，就知道每个月的closing balance了

腹黑男

在弱弱的问一下，这个最后问题“what was the range of the monthly closing balances of Carl’s account last year?”中的range怎么翻译啊？能不能帮我翻译下整个“what was the range of the monthly closing balances of Carl’s account last year?”句子呢？

腹黑男

OG 上解释了，不考虑利息，“no other transactions in the account last year”

更正一下，翻译OG上的解释：
条件1只能说明5月还是存钱的，以后存不存不知道
条件2只能说明6月是取钱的，以前取不取不知道

合起来根据5月closing balance，就知道每个月的closing balance了

-- by 会员 garlicwu (2011/8/5 18:16:37)

在弱弱的问一下，这个最后问题“what was the range of the monthly closing balances of Carl’s account last year?”中的range怎么翻译啊？能不能帮我翻译下整个“what was the range of the monthly closing balances of Carl’s account last year?”句子呢？

腹黑男

大家帮我翻译下吧

waltyi

range极差，即最大值减最小值
这题中求帐户余额的极差，就是用账户余额的最大值减最小值

腹黑男

range极差，即最大值减最小值
这题中求帐户余额的极差，就是用账户余额的最大值减最小值

-- by 会员 waltyi (2011/8/8 23:16:40)

谢谢你啦，太感谢了