Answer:
13 miles
Step-by-step explanation:
It may be easier to use a diagram but I am going to try my best to explain without one.
Picture their journey north as one side of a right angle triangle (a). Now picture their journey west as another side (b).
The shortest journey back is the hypotenuse of the triangle (c).
Using pythagoras you can work out the answer
[tex]a^{2} + b^{2} = c^{2}[/tex]
[tex]5^{2} + 12^{2} = c^{2}\\25 + 144 = c^{2} \\\\169 = c^{2}\\\sqrt{169} = c^{2} \\13 = c^{2}[/tex]
