问题
单项选择题
Questions refer to the following information.
In a marketing survey for products A, B, and C, 1,000 people were asked which of the products, if any, they use. The three circular regions in the diagram above represent the numbers of people who use products A, B, and C, according to the survey results. Of the people surveyed, a total of 400 use A, a total of 400 use B, and a total of 450 use C.
How many of the people surveyed use exactly one of the products
A．75
B．100
C．150
D．250
E．(E) 325
答案
参考答案：E
解析： 由上面的集合图可知，仅使用一种产品的人就是图中三个圆形区域不相交的部分所代表的人数，根据图形可得，仅使用A产品的人有：
400-125-125-75=75
仅使用B产品的人有：
400-125-75-100=100
仅使用C产品的人有：
450-125-75-100=150
所以仅使用一种产品的人共有：
75+100+150=325