GWD 1 数学两题

不知道哪里可以找到GWD31数学答案的解析和讨论，在这里麻烦各位啦。

这两题不知道怎么做。

Q30:

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

(1)     She bought $4.40 worth of stamps.

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

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.

这题我看来看去觉得应该选A吧，答案却是D，不知怎么得来的。

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

这个不知道怎么做？求解。

谢谢各位啦，20号考试。

谢谢啊，那第二题怎么做啊？

第二题还真是列举比较好。反正也不多嘛。

第一排A××，第二排××F，根据题意A和F的位置固定，只要排列BCDE就行了。E有两个位置，分别有3个和2个组合，所以一共5个。我想，可能这样去思考，速度会快些！