GWD数学疑问

syf1985085

1

What is the sum of a certain pair of consecutive odd integers?

(1)     At least one of the integers is negative.

(2)     At least one of the integers is positive.

                  

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.

不是很理解题意

2

On a map Town G is 10 centimeters due east of Town H and 8 centimeters due south of Town J.  Which of the following is closest to the straight-line distance, in centimeters, between Town H and Town J on the map?

 

A.     6

B.     13

C.     18

D.     20

E.      24

 

3

+	x	y	z
d			m
e		n
f

 

 

The figure above shows two entries, indicated by m and n, in an addition table.  What is the value of n + m?

(1)     d + y = -3

(2)     e + z = 12

                  

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.

dianecarton

第一题，问一对连续奇数的和是多少，只有两条件联立，能得到-1 1 和为O 选c

第二题，主要是理解三个点的位置关系，得到直角三角形hjg，勾股定理得到一个大约的答案13

第三题，看图，m=d+z  n=y+e  m+n=d+z+y+e 两条件联立，得到答案9 选c

graysytl

第三题可能你没读懂题

table右上角有个加号，结合起来理解就是，D+Z=M, E+Y=N

所以要知道M+N是多少，你就必须知道D+E+Y+Z

howren

What is the sum of a certain pair of consecutive odd integers?

(1)     At least one of the integers is negative.

(2)     At least one of the integers is positive.

不知道你懂了楼上的解答没有，我来举例说一下．连续奇数如－３，－１，１，３，问一对这样的连续数之和是什么？

条件１，至少一个为负数，－１＋１＝０（此时假设１个为负）；－３＋（－１）＝－４（此时假设２个为负），这样结果不确定，不充分；

条件２，也是一样，－１＋１＝０（此时１个为正），１＋３＝４（此时２个为正），结果也不确定

２个条件结合起来充分，因为只有一正一负存在，即１＋（－１）＝０