[讨论]GWD31套数学讨论：第二,三，四，六，八套

xin861123

各位战友，小弟在网上找了许久也没有看到GWD31套数学的讨论，很多都是讨论VERBAL的，但数学里很多题目知道答案却还是不知道怎么做，（过程！！）想在此向给位高手求救！！谢谢了~~

2-Q6:

The figure above shows the dimensions of a semicircular cross section of a one-way tunnel.  The single traffic lane is 12 feet wide and is equidistant from the sides of the tunnel.  If vehicles must clear the top of the tunnel by at least ½ foot when they are inside the traffic lane, what should be the limit on the height of vehicles that are allowed to use the tunnel?（实在对不起，图怎么也弄不上去，是一个半圆，直径是20FT）

                

                        

                

A.    5½ ft

B.    7½ ft

C.    8 ½ ft

D.    9½ ft

E.     10 ft

Answer: B

------------------------------------------------------------------------------------------------------------

3-Q14: 

How many seconds will it take for a car that is traveling at a constant rate of 45 miles per hour to travel a distance of 22 yards?     (1 mile = 1,160 yards)

A.    8

B.    9

C.    10

D.    11

E.     12

Answer: C

------------------------------------------------------------------------------------------------------------

3-Q18:

Last year the price per share of Stock X increased by k percent and the earnings per share of Stock X increased by m percent, where k is greater than m.  By what percent did the ratio of price per share to earnings per share increase, in terms of k and m?

A.    k/m %

B.    (k-m) %

C.    [100(k-m)]/(100+k) %

D.    [100(k-m)]/(100+m) %

E.     [100(k-m)]/(100+k+m) %

Answer: D

------------------------------------------------------------------------------------------------------------

4-Q13:

Lists S and T consist of the same number of positive integers.  Is the median of the integers in S greater than the average (arithmetic mean) of the integers in T?

(1)  The integers in S are consecutive even integers, and the integers in T are consecutive odd integers.

(2)    The sum of the integers in S is greater than the sum of the integers in T.

                  

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

------------------------------------------------------------------------------------------------------------

4-Q16:

In the sequence of nonzero numbers t₁, t₂, t₃, …, t_n, …, t_n+1 = t_n / 2 for all positive integers n.  What is the value of t₅?

(1)    t₃ = 1/4

(2)    t₁ - t₅ = 15/16
        

                                                                                                                              

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: D

------------------------------------------------------------------------------------------------------------

6-Q14:

A total of 30 percent of the geese included in a certain migration study were male.  If some of the geese migrated during the study and 20 percent of the migrating geese were male, what was the ratio of the migration rate for the male geese to the migration rate for the female geese?

[Migration rate for geese of a certain sex = (number of geese of that sex migrating) / (total number of geese of that sex)]

A.    1/4

B.    7/12

C.    2/3

D.    7/8

E.     8/7

Answer: B

------------------------------------------------------------------------------------------------------------

6-Q26:

K is a set of integers such that if the integer r is in K, then r + 1 is also in K.  Is 100 in
         K?

(1)    50 is in K.

(2)    150 is in K.

                  

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: A

------------------------------------------------------------------------------------------------------------

8-Q9:

If an integer n is to be chosen at random from the integers 1 to 96, inclusive, what is the probability that n(n + 1)(n + 2) will be divisible by 8?

 

Answer: 5/8 D

[此贴子已经被作者于2008-4-2 0:45:42编辑过]