重问大全-9-19

joywzy

19. In 1987 sinusitis was the most common chronic medical condition in the United States, followed by arthritis and high blood pressure, in that order.
The incidence rates for both arthritis and high blood pressure increase with age, but the incidence rate for sinusitis is the same for people of all ages.
The average age of the United States population will increase between 1987 and 2000.

Which of the following conclusions can be most properly drawn about chronic medical conditions in the United States from the information given above?
(A) Sinusitis will be more common than either arthritis or high blood pressure in 2000.
(B) Arthritis will be the most common chronic medical condition in 2000.
(C) The average age of people suffering from sinusitis will increase between 1987 and 2000.
(D) Fewer people will suffer from sinusitis in 2000 than suffered from it in 1987.
(E) A majority of the population will suffer from at least one of the medical conditions mentioned above by the year 2000.

答案：C

题干中the incidence rate for sinusitis is the same for people of all ages.不是与C矛盾吗？我选了D，用的是排除法，排除了A，B，C，E。

谢谢。

mindfree

又是一个数学题.

D是推不出来的. 另举一个例子, 我们每年要从一个公司的各级人员中挑两个人献血, 职员, 中级经理, 高级经理, executives. 现在知道今年各级人员的工资比前年都涨了6%, 由此我们能推出什么? 今年献血的人的平均工资比前年要高.

原文重点的句子就是"the incidence rate for sinusitis is the same for people of all ages", 相当于我举的例子中的两人, 既在各个年龄层的比例相同.

1stzhang

这个题目可以这样理解：
s在前　arthritis and high blood pressure　在后
后面的age增加，　s的age也增加。

cranberry

严重同意zhang,我们确定的只是人的平均年龄会增加，但顺序不是完全肯定，但S的比率不变，所以得S的平均年龄就增加了

joywzy

总算明白了，非常感谢!!!

请问做这种数学的逻辑题有什么好办法吗？我一碰到这种题就晕就错。

谢谢。

cranberry

还是真正读清题目，其实数字就是更精确的逻辑的一种表现，偶想不出捷径。

1stzhang

数学题目你不用读的特别清晰，但是必须知道两者或三者之间成正比或是反比。