扫描二维码，直接登录
题库 / OG2017Q-DS-294
Each of the 45 books on a shelf is written either in English or in Spanish, and each of the books is either a hardcover book or a paperback. If a book is to be selected at random from the books on the shelf, is the probability less than~$\frac{1}{2}$~that the book selected will be a paperback written in Spanish?
(1)Of the books on the shelf, 30 are paperbacks.
(2) Of the books on the shelf, 15 are written in Spanish.
Statement (1) ALONE is sufficient, but statement (2) alone is not sufficient.
Statement (2) ALONE is sufficient, but statement (1) alone is not sufficient.
BOTH statements TOGETHER are sufficient, but NEITHER statement ALONE is sufficient.
EACH statement ALONE is sufficient.
Statements (1) and (2) TOGETHER are NOT sufficient.
题目分析：
（1） 有30本平装书，因为不知道有其中有多少本是西班牙语书，因此也无法判断任取一本书为西班牙语平装书的概率是否小于1/2。
（2） 有15本西班牙书，这15本西班牙语书还包括精装和平装，因此，平装西班牙语书的数目小于或等于15本，所以任取一本书为西班牙语平装书的概率小于或等于15/45=1/3<1/2，题目得解。
因此，本题答案为（B），仅条件2可以解题，条件1不行。
读题，还是要理解。简单问题别复杂化。 #2 一共只有15本西班牙语书，所以平装精装，抽到西班牙语书的概率一定小于50%
登录 或 注册 后可以参加讨论