gwd19-10 gwd19-26 大家帮帮眼

sallyzhou

Q10

If $1,000 will be deposited in a bank account and I is the
dollar amount of interest earned from the original deposit, represented as I =
1000 {(1 + r/100)ⁿ – 1}, and the annual interest rate is r percent,
is r > 8 percent?

(1)   The deposit earns a total of $210 in interest in the first 2 years.

(2)    (1 + r/100)² > 1.15

（1）可以单独算出，充分

（2） 2*（r/100）+（r/100）*（r/100） >  15/100

r 是7.5也可以满足要求，所以r可能大于8，也可以小于8，不充分。

我选A, 但是答案给的是D,大家评评。

Q26:

How many different 6-letter sequences are there that consist

of 1 A, 2 B’s, and 3 C’s ？

A.   6    B.60  C.120  D.360  E.720

看了30分钟，也不知问什么，没办法，天性愚笨，大家帮帮我。

[此贴子已经被作者于2005-11-19 1:24:23编辑过]

sallyzhou

自己顶一下，大家帮帮我啊，好着急。