两个排列组合问题－－GWD31--1--2/25

lakeDZ

借地问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.

                                                                                          答案选D， 我选A。 谁能帮我讲解一下为什么B充分？

shiftmonkey

楼上我们的进度貌似差不多，呵呵

Q30我在版上也问了，不过到目前为止没有NN回答

不过我的想法跟你一样，。0.15和0.29这两种面值要凑成4.4只有一种情况，那就是都买10张；而条件二只给出了两个面值数量一样，但至于具体几张不得而知。所以我也觉得应该选A。