Answer:
9, four-seater cars
6, six-seater cars
Explanation:
Set up a system of equations
x is the number of 4-seater cars
y is the number of 6-seater cars
there is a total of 15 cars
x + y = 15
and there is a total of 72 people on the ride
4x + 6y = 72
so here is the system
x + y = 15
4x + 6y = 72
now use elimination to solve
x + y = 15 | * -4
4x + 6y = 72
-4x - 4y = -60
4x + 6y = 72
combine
2y = 12
solve using inverse operations
2y = 12
y = 6
now subsitute back in to find x
x + y = 15
y = 6
x + 6 = 15
inverse operations
x + 6 =1 5
x = 9