A typical car can hold four passengers and one driver, allowing five people to travel around. Given n number of people, return how many cars are needed to seat everyone comfortably.
carsNeeded(5) ➞ 1
carsNeeded(11) ➞ 3
carsNeeded(0) ➞ 0
It's likely there will be a few people left over and some cars won't be filled to max capacity.