Question

Mr. Katz's science class is planning a field trip. Thirty people are going on the trip. There are 7 drivers and two types of vehicles, vans and cars. Each van seats 6 people,including the driver, and each car seats 4 people, including a driver. If there are no extra seats in any of the vehicles, how many vans are taken?

Asking again because not sure on the answer still

Answer 1

5 vans are taken that's simple

Answer 2

Set up:

x=vans y=cars

x+y=7 6x+4y=30

To do the substitution, multiply the first equation by -4
6x+4y=30
-4x-4y=-28
-----------------
2x=2
x=1 number of vans

Just to finish it off plug it in the first equation to solve for cars.
6(1)+4y=30
6+4y=30
4y=24
y=6 number of cars

To double check: 1+6=7 number of drivers match.
6(1)+4(6)=30
6+24=30
30=30 number of people going on the trip

Hope that helps