Mark M. answered • 07/19/17

Tutor

4.9
(890)
Retired Math prof with teaching and tutoring experience in trig.

Draw a diagram!

Let x = distance from S to W Then, 12+2x = distance from W to D and distance from S to D = 4+4x

(Distance from S to W) + (Distance from W to D) = Distance from S to D

So, x + (12+2x) = 4 + 4x

3x + 12 = 4 + 4x

x = 8 miles