请教两道数学题

davidleezone · 发表于 2010-3-11 12:22:31

Q30:
Joanna bought only $0.15 stamps and $0.29 stamps. How many $0.15 stamps did she buy?
(1)    She bought $4.40 worth of stamps.
(2)    She bought an equal number of $0.15 stamps and $0.29 stamps.

A. Statement (1) ALONE is sufficient, but statement (2) alone is not sufficient.
B. Statement (2) ALONE is sufficient, but statement (1) alone is not sufficient.
C. BOTH statements TOGETHER are sufficient, but NEITHER statement ALONE is sufficient.
D. EACH statement ALONE is sufficient.
E. Statements (1) and (2) TOGETHER are NOT sufficient.
Answer:
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Q31:
A positive integer n is said to be “prime-saturated” if the product of all the different positive prime factors of n is less than the square root of n. What is the greatest two-digit prime-saturated integer?

A.   99
B.   98
C.   97
D.   96
E.   95
Answer:

davidleezone · 发表于 2010-3-11 12:30:37

第一题答案选D 我选C
如果只知道第二个条件的话：已知2种stamp价格和2种stamp的数量相等，怎么能求出买的一种stamp的数量呢？

第二题答案选D 我选B
98的prime factor 1和7 < square root of 98 啊~

来人指导指导啊！

dongnannan · 发表于 2010-3-11 12:36:52

我觉得吧，第一题的确应该是D，因为$0.29和$0.15只能分成各十张来凑齐$4.4的这个总值。条件二也是这个原因，只能是这种分法才满足数量相同的条件。

第二题98的prime factors 有1、2、7 加起来超过了squar root of 98。

个人见解啊，还需要牛人来确认

davidleezone · 发表于 2010-3-11 14:12:25

第二题看懂了··· 少算了一个2~~~

第一题由第一个条件可以算出··第二个条件觉得不可以吧

请教两道数学题

所属分类: GMAT考试

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