Transcript

NARRATOR:

Suppose the dealership had all cars. That would mean there were 84 wheels, because 21 times 4 is 84. But you've been told by Paul there are only 54 wheels. That means there are 30 wheels too many, as 84 take away 54 is 30.

To solve this, you need to change some cars into motorbikes. When a car changes into a motorbike, it loses 2 wheels. Therefore, you need to divide the number of wheels you have too many, that's 30, by 2. 30 divided by 2 is 15. So, 15 cars to change into motorbikes.