gwd 17-13

rosebudxiaojie

Q13:

Juan bought some paperback books that cost $8 each and some hardcover books that cost $25 each.  If Juan bought more than 10 paperback books, how many hardcover books did he buy?

(1)     The total cost of the hardcover books that Juan bought was at least $150.

(2)     The total cost of all the books that Juan bought was less than $260.

                  

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

我选E

laihong

E

leonchan

E

sunshine001

C. Let P as # of paperbacks, H as hardcovers

(1) 25H > 150, H > 6. Not sufficient

(2) 8P + 25H < 260. Not sufficient

(1) and (2): If H > 6, P > 10, and 8P + 25H < 260 -->

If P = 11, H = 7,

If P = 12, H = 7,

If P = 13, H = 6, violates (1)

So Juan brought 7 hardcover books.

wzhyan

答案为C

H >= 6, P > 10,

Suppose     H = 6    = 11         25H+ 8P=238    < 260       OK

                 H = 6    = 12         25H+ 8P=246    < 260        OK

                 H = 6    = 13         25H+ 8P=254    < 260       OK

                H = 6    = 14         25H+ 8P=260                   violates

                 H = 7    = 11         25H+ 8P=263     >260      violates

So Juan bought 6 hardcover books

[此贴子已经被作者于2005-11-21 20:15:12编辑过]

jinghezhao

wo xuan E

eSpirit

以下是引用rosebudxiaojie在2005-11-18 16:33:00的发言：

Q13:

Juan bought some paperback books that cost $8 each and some hardcover books that cost $25 each.  If Juan bought more than 10 paperback books, how many hardcover books did he buy?

(1)     The total cost of the hardcover books that Juan bought was at least $150.

(2)     The total cost of all the books that Juan bought was less than $260.

其实答案的关键在于at least如何理解的问题，是应该理解成“大于等于”还是“大于”。如果是“大于等于”的话，应该选E，如果是“大于”的话应该选C。

wining

那at least 到底该如何理解才对啊?

riverhouse

k

shaojin

I agree C