Three student teams collected 65 books for the school library. the first team collected 10 fewer books than the second team and the third team collected 30% of the number of books collected by first and second teams together. how many books did each team collect?

Given:
3 student teams
65 total number of books collected
first team collected 10 fewer books than the second team
the third team collected 30% of the number of books collected by first and second teams together

Let x represent the books collected by the 2nd team.

1st team: (x - 10)
2nd team: x
3rd team: 30%[x + (x-10)]

(x-10) + x + 30%[x + (x - 10)] = 65
x - 10 + x + 0.3x + 0.3x - 3 = 65
x + x + 0.3x + 0.3x = 65 + 10 + 3
2.6x = 78
x = 78/2.6
x = 30

1st team: x - 10 → 30 - 10 = 20
2nd team: x → 30
3rd team: 30%[x + (x-10)] → 0.3(30 + 30 - 10) = 0.30 (50) = 15

20 + 30 + 15 = 65

1st team got 20 books.
2nd team got 30 books.
3rd team got 15 books. 
For a total of 65 books.

There are three teams that collected a total of 65 books
Team 1 -x
Team 2- x+ 10
As team 2 collected 10 books more than team 1
Team 3 -30% of (x + x+ 10)
Team 3 collected 30% of the books that team 1 and team 2 collected in total
The equation for the total number of books is;
x + x + 10 + 0.3(2x+10) = 65
2x + 10 + 0.6x + 3 = 65
2.6x +13 = 65
2.6x = 52
x = 20
Team 1-20 books
Team 2 -30 books and
Team 3 - 15 books