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吧。
今日练习题为数学题，题目如下
Of all the students in a certain dormitory, 1/2 are first-year students and the rest are second-year students. If 4/5 of the first-year students have not declared a major and if the fraction of second-year students who have declared a major is 3 times the fraction of first-year students who have declared a major, what fraction of all the students in the dormitory are second-year students who have not declared a major?
A 1/15
B 1/5
C 4/15
D 1/3
E 2/5
正确答案：
B
解题思路：
设总人数为100，那么，一年级学生有50个，二年级50个。一年级中没定专业的有40个，定了的有10个。由于二年级学生中定了专业的比例是一年级的3倍，所以二年级学生定了专业的有30个，没定专业的有20个。所以，二年级学生中，没定专业的人数与总人数的比例是20%，即1/5
