Answer:
7 cars
11 bikes
Explanation:
18 cars would have 72 tires. This is 22 more tires than necessary. If we add a bike, we lose four tires (from the car) and add two (from the bike). This means we lose two tires. 22/2 is 11 so it would be 11 bikes and 7 cars.
11 bikes = 22 tires
7 cars = 28 tires
22+28=50 tires