Answer:5 vans  7 cars
Step-by-step explanation:
c=cars     v=vans
c+v= 12
c =( 12-v)
11v + 4(12-v) = 83
11v + 48-4v = 83
7v = 35
v= 5
c = 12-5 Â Â Â Â c = 7
7 cars x 4 students = 28 students
5 vans x 11 students = 55 students
55+28 = 83 students