Answer:
Drew saves a distance of
by taking the shortcut.
Step-by-step explanation:
Here is an image of the routes.
We have drawn it assigning the signs NSEW where N=North,S=South ,E=East and W=West.
Now the total distance covered by Drew = OA+AB+BC 
We see by joining C with O it has a shortcut.
And it forms a right angled triangle.
,
at D.
By using Pythagoras theorem we can find the shortcut distance.
OC is the hypotenuse and 
So Drew saves
of distance following the advice of his friend and opting for the shortcut route.