This question is actually a roundabout question: it is not very difficult. According to the topic, we can get: 5/4a= 2/3b=c, so we can look at it this way. Let's compare the size of ab first, 5/4a= 2/3b, and both sides are multiplied by 4/5, and a=5/6b, which means 6a=5b, that is, 6 A equals 5 B. If we buy a fruit, A spends 6 yuan and B spends it. We think it is most suitable when we spend less. (This piece is very important! Conclusion: In the equation, when the product of numbers and letters is divided by the comparison size, the larger the number, the smallest the result. So this person understands.

When this problem is 5/4a=2/3b=c, the comparison size is 15/ 12a = 8/12b = c to see who uses it the most:15/12a, c, 8. c & gt 15/ 12a