Aschool bus has 25 seats, with 5 rows of 5 szt. 15 students from the first grade and 5 students from the second grade travel in the bus. how many
ways can the students be seated if all of the second grade students rupy the first rour?

Technically only 1...

If you have to use 4 rows there is only one option;
1 1 1 2
1 1 2 1
1 2 1 1
2 1 1 1

Each number represents the total kids in a row.
1st number is row 1 second number is row 2 etc.

If you can use 2 or 3 rows there are some more answers.