1) How much larger or smaller the image will be depends on the scale factor in a mathematical object's dilatation (compared to the original object). When the scaling factor's absolute value exceeds 1, an expansion takes place.
2) No. scale factors can’t be rational numbers. Scaling up always involves a scale factor larger than 1. Let's put this in the formula, which makes it: 15 5 = 3, for instance, if the larger figure's dimension is 15 and the smaller one's is 5. As a result, it is clear that the scale factor is higher than 1.