Answer:
a) 16 vehicles
b) (x + y) vehicles
Step-by-step explanation:
According to US traffic laws, bicycles are also considered to be vehicles since they are a mode of transport as they can attain speeds far more than humans walking.
Now, if there are 12 bicycles and 4 cars, it means;
Number of vehicles = 12 + 4 = 16 vehicles.
If there are x bicycles and y cars, it means;
Number of vehicles = (x + y) vehicles