求解og原题两道，看不懂题，望各位高人指教

Padmeelena

160 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.


2 163. In a certain business, production index p is directly
proportional to effi ciency index e, which is in turn
directly proportional to investment index i. What is p if
i = 70 ?
(1) e = 0.5 whenever i = 60.
(2) p = 2.0 whenever i = 50.


题目看不明白，非常感谢！

nioni

2 163. In a certain business, production index p is directly
proportional to effi ciency index e, which is in turn
directly proportional to investment index i. What is p if
i = 70 ?
(1) e = 0.5 whenever i = 60.
(2) p = 2.0 whenever i = 50.
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这个题意思是p与e成比例，然后e与i成比例，然后问如果i是70，那么p是多少？
（1）当i=60的时候e等于0.5
（2）当i=50的时候p等于2
对于（1）这个时候只能求出e，不能求出p
对于（2）可以求出p
因此（2）充分，选B
至于第一题，我有个地方不太懂，帮不了，等NN

Padmeelena

谢谢啦

gaor

160 我的理解是：
条件一：4月底的金额小于2625，说明5月15号还处于存款状态
条件二：6月底的金额小于2675，说明6月份没有存款，但有$50取款

问题是问去年12个月每个月月底金额数的区间，所以应该C,两个条件同时才能得出结果

btw标准答案是什么？

nioni

那之前说的去年5月份的时候的closing account有2500是不是不仅仅有存进去或取出来的money，应该有一年之前的余额吧，当时我就这个地方不清楚，觉得有些奇怪

gaor

是有一年之前的余额

但已知5月balance是$2,600, 条件一是说4月份balance小于$2625，如果5月开始取款$50，5月balance应该小于$2575，所以5月一定是还在继续存款$120