Answer:
64:16 (Simplified is 4:1) For every 4 passengers, there is 1 car.
Whatever group is first, you put the amount of items in that group first in the ratio. (Since it's comparing passengers to cars, you put the amount of passengers first.) Then, simply divide both sides by their GCF (Greatest Common Factor) which is 16. So, the ratio you're left with is 4:1 (4 passengers for every 1 car)
