Step-by-step explanation:
the answer should be 18
Answer:

Step-by-step explanation:
Given
--- scale factor
Required [missing from the question]:
The ratio of width of the model to the original
From the question, we understand that the scale factor is: 2 : 15
The ratio of the width of the model to the original equals the given scale factor i.e.

The answer is the first one; it is an arithmetic sequence with a common difference of -40.