Step-by-step explanation:
The "scale" of a model is it's size relative to the size of the "real" version. So compared to a 1:24 scale model, the real version is 24 times larger in size or 1:1 in scale. The model on top is "1:18 Scale", which means it is one eighteenth the size of the real thing. So basically scale models are based on a scale of the real thing (of whatever thing it is, like a car). While models are not, they can be any size.