The original ratio of class A and class B is 5:4. If nine people are transferred from Class A to class B, then the ratio of class B to class A is 5:4. How many people are there in each class?

The total number of people in two classes: 9 △ 55 + 4-45 + 4, = 9 △ 59-49, = 9 △ 19, = 81 (people); class A: 81 × 59 = 45 (people), class B: 81 × 49 = 36 (people). Answer: there are 45 people in class A and 36 people in class B

The number of workers in the first workshop is more than 3 / 4 of that in the second workshop,
If 30 people are transferred from the second workshop to the first workshop, the number of workers in the second workshop will become half of the number of workers in the first workshop

There are x people in the second workshop and 3 / 4 x + 10 people in the first workshop
（3/4 X＋10＋30）×1/2＝X－30
3/8 X＋20＝X－30
5/8 X＝50
X＝50÷5/8
X＝80
Workshop 1: 80 × 3 / 4 + 10 = 70
The number of workers in the first workshop is more than 10 people, which is 3 / 4 of the number of workers in the second workshop. If 30 people are transferred from the second workshop to the first workshop, the number of workers in the second workshop will become half of the number of workers in the first workshop

There are three classes in the preparatory grade of a school, with a total of 130 students. Class B is 7 / 8 of class A, and class A is 6 / 5 of class C
2) Xiaojie's mother bought two kinds of stocks and spent 5000 yuan each. One of them earned 25% and the other lost 25%. Judge whether Xiaojie's mother made or lost, or not

There are three classes in the preparatory grade of a school, with a total of 130 students. Class B is 7 / 8 of class A, and class A is 6 / 5 of class C
Take class A as unit 1 (or set it to x, all the same) and class B has 7 / 8 (7 / 8x)
Class C has 1 / (5 / 6) = 5 / 6 (or 5 / 6x)
According to the meaning of the title
Class A has 130 / (1 + 7 / 8 + 5 / 6) = 130 / (65 / 24) = 48
Class B has 48 × 7 / 8 = 42 people
Class C has 48 × 5 / 6 = 40 people
Or x + 7 / 8x + 5 / 6x = 130
X = 48
Xiaojie's mother bought two kinds of stocks and spent 5000 yuan each. One of them earned 25% and the other lost 25%. Judge whether Xiaojie's mother made or lost, or not
Cost = 5000 × 2 = 10000 yuan
Total revenue = 5000 × (1 + 25%) + 5000 × (1-25%) = 10000 yuan
No gain, no loss

The ratio of class A to class B is five to seven. After class B transfers two people to the deck, the ratio of class A to class B is four to five
How many people?

The ratio of class A to class B is five to seven. After two people are transferred from class B to class A, the ratio of class A to class B is four to five. How many students are there in class A and how many students are there in class B

The original ratio of class A and class B is 5:4. If nine people are transferred from Class A to class B, then the ratio of class B to class A is 5:4. How many people are there in each class?