The answer is <span>D. x=y-z-9/7</span>
The two ways to find the ratio of the length is to turn the inches into feet or the feet into inches
So the answer can be solved like this:
1/36ft to 1/4ft which is 9:1 (blueprint size to actual size)
or
1/3in to 3in which is also 9:1 (blueprint size to actual size)