0.3 inches per hour, if I did the math correctly.
Step-by-step explanation:

Answer:
x=y-4
Step-by-step explanation:
y=x+4
-4
y-4=x
The gradient of the perpendicular line would be the negative reciprocal of the original line. Therefore the gradient of the perpendicular line would be -2/5x.
Since we know y=mx+c, ∴y=-2/5x+c. Sub in the x and y values of the given point and we get that c=26/5.
The perpendicular equation would be y=-2/5x+26/5.
I hope I got this right.
15 is the answer i divided