5.7 of anything minus 3.9 of the same thing leaves 1.8 of them.
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.

6ft and 3 inches is 190.5cm
7^5/4 would be the answer to the question I think you are asking