The number of trees planted in the first class accounts for 1 / 5 of the total number of the three classes. The ratio of trees planted in the second class to the third class is 3:5, Class 1 Planted 40 trees less than Class 2. How many trees were planted in three classes

One class accounts for one fifth of the total number of three classes
Class 2 and class 3 account for 1-1 / 5 = 4 / 5 of the total
The tree planting ratio of class 2 and class 3 is 3 to 5
Then the second class accounts for 4 / 5 of the total number of the second and third classes △ (5 + 3) × 3 = 3 / 10
A total of 40 trees were planted in 3 classes (3 / 10-1 / 5) = 400

During the tree Festival, 100 trees were planted in class 51 and class 52, 120 trees in class 51 and class 53, and three seventh of the total number of trees planted in class 51,
How many trees are there in three classes?

(100+120）÷（1+3/7）
=220÷10/7
=154 trees

The first group accounts for three fifths of the total number of the other two groups, the second group accounts for one third of the total number of the other two groups, and the third group has 51 people
How many trees are planted in three groups?

The first group accounts for three fifths of the total number of the other two groups
The first group accounts for 5 / 13 of the total number of the other two groups
The number of trees planted in the first group is 5 / 13 of the total number of trees planted in the other two groups, so the ratio of the number of trees planted in the first group to the number of trees planted in the other two groups is 3:15, and the number of trees planted in the first group is 5 / 18 of the total number;
The number of trees planted in the second group is 1 / 3 of the total number of the other two groups, so the ratio of the number of trees planted in the second group to the number of trees planted in the other two groups is 1:3, and the number of trees planted in the second group is 1 / 4 of the total number;
In the third group, the number of trees is 51 (1-5 / 18-1 / 4)
The formula is 51 ^ (1-5 / 18-1 / 4)
=51÷（13/18－1/4）
=51÷17/36
=51×36/17
=108 trees;
A: 108 trees were planted in the three groups

The number of trees planted in the first class accounts for 1 / 5 of the total number of the three classes. The ratio of trees planted in the second class to the third class is 3:5, Class 1 Planted 40 trees less than Class 2. How many trees were planted in three classes