有些关于比或倍数的应用题,两个量是倍数关系,当两个数量发生变化后,倍数关系也发生变化,因此,我们可在变量中寻找不变的量,再进行分析与解答。例1:甲、乙两个同学,某次考试的分数比是5:4,如果甲少得20分,乙多得20分,这时他们的分数比是5:7,问甲、乙两人原来的考试分数各是多少?分析与解答:因为甲、乙两人一个少得20分,一个多得20分,因此两人的分数之和没有发生变化,原来两人分 Some questions about the ratio or multiple, the two quantities are multiples of the relationship, when the two changes in the number of times, the relationship between the multiple changes, so we can look for variables in the same amount, and then analyze and answer. Example 1: A, B two students, the score of a test score is 5: 4, if A less 20 points, B more than 20 points, then their score ratio is 5: 7, ask A, B two People’s original test scores are each how? Analysis and Answers: Because A, B two a little 20 points, one more 20 points, so the two did not change the sum of the scores, the original two points