Let V be the number of students that fit inside a van and B the number of students that fit inside a bus. Since 366 students fit in 2 vans and 6 buses, then:

Since 213 students fit in 6 vans and 3 buses, then:

Multiply the second equation by 2:

Then, we have the system:

Substract the first equation from the second one and solve for V:

Substitute V=6 into the first equation and solve for B:

Therefore, a van has 6 students and a bus has 59 students.