The question is "What is the scale of the model to the actual statue"
That means you must put 2/15.
2 being the model
15 being the actual statue
Take that fraction and equal is to 1/x.
Multiply 15 to 1 and 2 to x.
In the end, to solve, you divide 15 by 2x.
The answer is X=7.5
1 : 7.5