The car traveled 11 miles.
I think this is a trick question, mean to have you draw triangles. If not meant to be a "where did they bury the survivors" type of question, it's poorly worded.
If the problem is looking for "as the crow flies" distance between the beginning and ending points, then we'd look at it on graph. Starting from 0,0, the car would end up at 3,4. We can find that distance.
