【备考每日练】GMAT数学真题精选实例讲解（第九练）

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GMAT备考，除了背背背，更重要的就是练练练!通过练习，巩固知识，熟练技巧，最终才能在GMAT考试中发挥出色，取得好成绩，所以练习的重要性不言而喻。因此，小编为大家精心准备了GMAT考试各类题型的练习题和答案解析，帮助大家每日一练，为考试做好准备。一起来看今天的题目。

今日练习题为数学题，题目如下

The figure shown represents a board with 4 rows of pegs, and at the bottom of

the board are 4 cells numbered 1 to 4. Whenever the ball shown passes through

the opening between two adjacent pegs in the same row, it will hit the peg

directly beneath the opening. The ball then has the probability 1/2 of passing

through the opening immediately to the left of that peg and probability 1/2 of

passing through the opening immediately to the right. What is the probability

that when the ball passes through the first two pegs at the top it will end in

Cell 2?

正确答案：

D

题目翻译：

如果一个球穿过某一行某两个桩中间的空间，那它一定会碰到下一行的那个桩,而每碰到一次，球往左和往右走的概率都是50%，现在有一个球掉进了最上面那行的两个桩中间，请问落进最下面一行第2和第3个桩之间的“Cell2”的概率。

解题思路：

把概率累加一下就可以了。第二行就是50%/50%。第三行是25%/50%/25%。那最后一行就是12.5%/37.5%/37.5%/12.5%。所以掉进Cell2的几率是37.5%，也就是D选项。