几道PREP数学题不会，请求高人指导

audrey1007

Q25:

A photographer will arrange 6 people of 6 different heights for photograph by placing them in two rows of three so that each person in the first row is standing in front of someone in the second row.  The heights of the people within each row must increase from left to right, and each person in the second row must be taller than the person standing in front of him or her.  How many such arrangements of the 6 people are possible?

 

A.
                        5

B.
                        6

C.
                        9

D.
                        24

E.  36

Q26:

Running at their respective constant rates, machine X takes 2 days longer to produce w widgets than machine Y.  At these rates, if the two machines together produce 5/4 w widgets in 3 days, how many days would it take machine X alone to produce 2w widgets?

 

A.
                        4

B.
                        6

C.
                        8

D.
                        10

E.  12

Q29:

June 25, 1982, fell on a Friday.  On which day of the week did June 25, 1987, fall?  (Note: 1984 was a leap year.)

 

A.
                        Sunday

B.
                        Monday

C.
                        Tuesday

D.
                        Wednesday

E.  Thursday

F.   Q30:

G.
                        Joanna bought only $0.15 stamps and $0.29 stamps.  How many $0.15 stamps did she buy?

H.
                        (1)
                      She bought $4.40 worth of stamps.

I.     (2)
                      She bought an equal number of $0.15 stamps and $0.29 stamps.

J.   

K.
                        A. Statement (1) ALONE is sufficient, but statement (2) alone is not sufficient.

L.  B. Statement (2) ALONE is sufficient, but statement (1) alone is not sufficient.

M.
                        C. BOTH statements TOGETHER are sufficient, but NEITHER statement ALONE is sufficient.

N.
                        D. EACH statement ALONE is sufficient.

O.
                        E. Statements (1) and (2) TOGETHER are NOT sufficient.

P.   Q35:

Q.
                        What is the median number of employees assigned per project for the projects at Company Z?

R.
                        (1)
                    25 percent of the projects at Company Z have 4 or more employees assigned to each project.

S.   (2)    35 percent of the projects at Company Z have 2 or fewer employees assigned to each project.

T. 

U.
                        A. Statement (1) ALONE is sufficient, but statement (2) alone is not sufficient.

V.
                        B. Statement (2) ALONE is sufficient, but statement (1) alone is not sufficient.

W.              C. BOTH statements TOGETHER are sufficient, but NEITHER statement ALONE is sufficient.

X.
                        D. EACH statement ALONE is sufficient.

Y.
                        E. Statements (1) and (2) TOGETHER are NOT sufficient.

 

snake37

第一题：我也不会别的办法，而且我模考的时候也遇到这题了，我就枚举的，结果还是错了，可能这道题就是考细心的吧！
第二题：选项代入法，一个个试是最省时间的方法！
第三题：所求日期是1982年6月25日后的第（365+366+365+365+365）=1826天。1826/7余数是6，6+5-7=4，因此所求日期是周四。
第四题：方程15X+29Y=440，X,Y均为正整数，此方程有唯一解，X=10，Y=10,所以选A
第五题：前25%大于等于4，后35%小于等于2，中间的40%只能是3

audrey1007

直到今天才看到，谢谢上面的大侠了……

sjtupeeler

第一道题目可以知道1只能在第一排的最左面，根据这一点可以轻松得到以后的答案了

Ashley_7

第三题余数为4，那答案不应该是周二么？

另外第一题结果是3伐？

zhang90_3

第一题可知1只能在第一排最左面，6只能在第二排最右面，这样 2有两个位置，第二排最左或者第一排中间， 然后分这两种情况列举咯， 我的答案是A 5种 ，不知道对不

audrey1007

对，答案是5种