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标题: GMAT Prep 1 上两道数学题求解 [打印本页]

作者: topmba2010 时间: 2009-10-20 21:43 标题: GMAT Prep 1 上两道数学题求解

官方软件上的两道题：

1）第一道，关于加法，我怎么从来没这样算过加法，希望哪位牛人指教：

+ |X Y Z
_________
4 |1 -5 M
E |7 N 10
F |2 -4 5

求M+N的值。选项： -19； 4； 5； 6； 22；（5是对的。）

2）等腰三角形;判断数据充分。
in isosceles RST, what is the measure of R?
(1) the measure of angle T = 100
(2) the measure of angle S = 40

我认为（1）和（2）都独自充分，所以选（D）因为在等腰三角形中，知道任何一个角，就可以求出另外两个角。为什么答案说是A呢？

作者: topmba2010 时间: 2009-10-26 23:06

今天在GWD数学第7套Q23又见到这类加法，真是晕。。。。。。

QUOTE:

Q23: [还是不懂这类题怎么做！]

+	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.

Answer: C

作者: topmba2010 时间: 2009-10-26 23:08

数学 GWD-7-23

Q23: [还是不懂这类题怎么做！]

+	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.

Answer: C

作者: topmba2010 时间: 2009-10-26 23:09

尝试两次都不能粘贴。

今天在GWD数学7第23题又看到这种加法，希望有NN指教！

作者: miaoyin_tx 时间: 2009-10-27 09:51

QUOTE:

以下是引用topmba2010在2009-10-26 23:09:00的发言：
尝试两次都不能粘贴。

今天在GWD数学7第23题又看到这种加法，希望有NN指教！

再试试像一堵庐山真面目

作者: topmba2010 时间: 2009-10-28 01:43

Q23:

+    |   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.

Answer:    C

作者: topmba2010 时间: 2009-10-28 02:50

奈奈的，等了半天的回帖，居然是一个spam!请问有人会做加法吗？？？

多谢了！！！

作者: topmba2010 时间: 2009-10-28 23:24

好了，还是自问自答吧：其实就是简单的加法矩阵，一开始把我迷惑住了，没什么大不了的。。。。

官方软件上的：

1）

+ |X Y Z
_________
4 |1 -5 M
E |7 N 10
F |2 -4 5

求M+N的值。选项： -19； 4； 5； 6； 22；（5是对的。）

这种写法就是把XYZ 和4EF的每位数对于加起来，结果在中间的3x3的方格内。

4+X=1 --> X=-3, 4+Y=-5 -->Y=-9,
E+X=7 --> E=10, E+Y=N -->N=10+(-9)=1
F+X=2 --> F=2-X=5, and of course F+Y=5-9=-4, checks!
F+Z=5 --> Z=0, 4+Z=M --> M=4
Therefore, M+N=5.

不敢相信这样的题我都不会！！

2）

GWD-7-Q23:

+    |   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

同理： d+z=m, e+y=n, --> m+n=d+z+e+y = -3+12 = 9.
所以需要两个条件同时成立！选C。

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