Final answer:
The scale factor of the enlargement from a 24 cm by 30 cm photo to a 60 cm by 75 cm photo is found by dividing the dimensions of the enlarged photo by the original photo, resulting in a scale factor of 2.5.
Step-by-step explanation:
To determine the scale factor of the enlargement of a photo, we compare the dimensions of the enlarged photo to the original photo. This is done by dividing a dimension of the enlarged photo by the corresponding dimension of the original photo. Since both dimensions (length and width) should be increased by the same scale factor for the photo to maintain its proportions, it's sufficient to compare one set of corresponding dimensions.
In this case, the original photo has a width of 24 cm and the enlarged photo has a width of 60 cm. To find the scale factor, we divide the width of the enlarged photo by the width of the original photo:
Scale Factor = Width of Enlarged Photo / Width of Original Photo
Scale Factor = 60 cm / 24 cm = 2.5
Therefore, the scale factor of the enlargement is 2.5, which corresponds to option (b).