Q1: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 t

Q1: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 t
Q1:
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
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.
我不明白（2）为什么能推出结论.
If n is a positive integer,what is the remainder when (74n + 3)(6n) is divided by 10
A.1
B.2
C.4
D.6
E.8
Q3:
A certain list consists of 3 different numbers.Does the median of the 3 numbers equal the average (arithmetic mean) of the 3 numbers?
(1) The range of the 3 numbers is equal to twice the difference between the greatest number and the median.
(2) The sum of the 3 numbers is equal to 3 times one of the numbers.
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
我不明白为什么（2）能推出结论.

Q1: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 t
我又来了,哈哈
Q1：GWD数学里的一道争议题,国内外论坛都有所讨论
第一种观点是答案错误
statement (1):r=10>8,Sufficient
statement (2):要使r>8,(1 + r/100)^2必大于1.1664,(1 + r/100)^2>1.15,r可能大于也可能小于8,Insufficient
选B
第二种观点是题目错误
statement (2)应为：(1 + r/100)2 > 1.5,这样r恒大于8,Sufficient
就选择D了
Q2：余数
LZ问的很可能是这道题：（来源：GWD Math-25-7）
If n is a positive integer,what is the remainder,When (7^(4n+3))(6^n) is divided by 10?
由于除数为10,一个数除以10其余数必为这个数个位数,如12/10 remainder=2,123/10 remainder=3…
因此,我们只需要知道7^(4n+3)与6^n乘积的个位数是多少即可,也就是7^(4n+3)个位数与6^n个位数的乘积的个位数.
N 1 2 3 4 5 …
units digit of 7^n 7 9 3 1 7 …
units digit of 6^n 6 6 6 6 6 …
由上表可知,7^(4n+3)的个位数恒等于3,6^n的个位数恒等于6,那么3*6=18,个位数为8,选E
Q3：不等式
根据已知条件：三个不同的数,设为A,B,C,A

Q1: 因为(2)可以解出r，所以可以知道是否r>8%。
Q2: 此题有问题，当n=1，(74n+3)(6n)=462，is divided by 10，the remainder is 2。是不是我理解错了。
Q3: 设3个数是a、b、c，按大小顺序排列，且b是median。
the median of the 3 numbers equals the average (...

全部展开

Q1: 因为(2)可以解出r，所以可以知道是否r>8%。
Q2: 此题有问题，当n=1，(74n+3)(6n)=462，is divided by 10，the remainder is 2。是不是我理解错了。
Q3: 设3个数是a、b、c，按大小顺序排列，且b是median。
the median of the 3 numbers equals the average (arithmetic mean) of the 3numbers 意思是
b= (a+b+c)/3即 2b=a+c
(2) The sum of the 3 numbersis equal to 3 times one of the numbers 意思是
3b=a+b+c即2b=a+c
相同。

收起