[原创]GWD21 MATH答案同大家探讨

刚做了GWD21的MATH部分，但有些题看不到数字，所以没做。

1C 2C 3A 4D 5D 6A 7C 8D 9.D 10B 11E 12A 13D 14B 15D 16E 17C 18A 19E 20C 21E 22A 23C 24E 25A 26B 27C 28D 29E 30C 31E 32D 33A 34D 35D 36B 37D

为方便看，另一种形式：

CCADD  ACDDB  EADBD ECAEC EACEA BCDEC EDADD BD

谢谢美女斑斑！

不好意思，刚才在做VERBAL，才看到帖子。

CCADD  ABDDB  EADBD  ECAEE AACEA  CCDEC  EDADD  BD

对下, 不知道对不对?

等我把剩余未做的部分都做了，再跟MM对。

hitlzc:CCADD  AEDDB  BADBD ECAEC EECEA BCDBC EDADD BD

tomacy:CCADD  ABDDB  EADBD  ECAEE AACEA  CCDEC  EDADD  BD

7/11/20/21/22/26/29不同

再看一次的结果

Q7:

In the xy-plane, line a and line b have the same slope.  If the y-intercept of line a is –1, what is the y-intercept of line b ?

(1)     The x-intercept of line a is –1.

(2)     Line b passes through the point (10, 20).

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.

认为选C

思路：设line a: y=mx+n, b: y=mx+c,题干知n=-1，求c=?

1)得m=-1

2）10m+c=20

二者结合，才能求出C

Q11:

If n is an integer, is 10ⁿ ≤ 0.001 ?

(1)     n ≤ -2

(2)     n > -5

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.

同意tomacy,选E

Q20:

Of the 60 animals on a certain farm, 2/3are either pigs or cows.  How many of the animals are cows?

(1)     The farm has more than twice as many cows as it has pigs.

(2)     The farm has more than 12 pigs.

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.

仍坚持选C

思路：题干知道pig+cow=60*2/3=40

1)cow>2*pig

2)pig>12

结合有3*pig<40,12<pig<40/3,则pig=13

Q21:

A store purchased a Brand C computer for the same amount that it paid for a Brand D computer and then sold them both at higher prices.  The store’s gross profit on the Brand C computer was what percent greater than its gross profit on the Brand D computer?

(1)   The price at which the store sold the Brand C computer was 15 percent greater than the price at which the store sold the Brand D computer.

(2)     The store’s gross profit on the Brand D computer was $300.

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.

仍坚持选E

并没说成本的关系，怎么会知道利润的关系呢？

Q22:

In triangle ABC, point X is the midpoint of side AC and point Y is the midpoint of side BC.  If point R is the midpoint of line segment XC and if point S is the midpoint of line segment YC, what is the area of triangular region RCS ?

(1)     The area of triangular region ABX is 32.

(2)     The length of one of the altitudes of triangle ABC is 8.

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.

仍坚持选E

1）在缺少条件的情况下，三角形ABX和RCS没有明确的比例关系。

2）知道一个高，并不知道是那个高

Q26:

For each positive integer n, the integer n^* is defined by n^* = n² + 1.  What is the value of the positive integer k ?

(1)     When k is divided by 4, the remainder is 1.

(2)     18 ≤ k^* ≤ 36

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.

仍坚持选B

2）18 ≤ k^* ≤ 36，则18 ≤ k^2+1 ≤ 36,17 ≤ k^2≤ 35,k是正整数，4^2<17,6^2>35,所以只能是5

Q29:同意tomacy,选E

现更新答案如下：CCADD  ACDDB  EADBD ECAEC EECEA BCDEC EDADD BD

并在一楼更新

Q22:

In triangle ABC, point X is the midpoint of side AC and point Y is the midpoint of side BC.  If point R is the midpoint of line segment XC and if point S is the midpoint of line segment YC, what is the area of triangular region RCS ?

(1)     The area of triangular region ABX is 32.

(2)     The length of one of the altitudes of triangle ABC is 8.

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.

仍坚持选E

1）在缺少条件的情况下，三角形ABX和RCS没有明确的比例关系。

-------RS是ABC长度的1/4, SC 是BC的1/4, RC 是AC 的1/4 ===> RSC 是ABC 的1/16

       ABC = 2* ABX ==> 2*32=64 ===> RSC = 4

2）知道一个高，并不知道是那个高

-------两个三角形 share 同一条高.

因此答案是A, 其他都同意, 谢谢hitlzc.