Also, for this answer, I'm assuming that the 'expressway' mentioned in your question is the top horizontal line. (In fact, that must be the expressway, since there would be no other way to solve the problem)
Okay, let's get started. For starters, GY = 16 ft. That much is given to us in the question. GY's equivalent is BX, which is 10 ft. When the angles are mirrored like they are across the 'expressway' in this problem, they do not change, so we only need to put the dimensions to scale. If we divide 10 / 16, we see that the scale-down factor is .625, or 62.5%. With this information, we can find the length of XW.
How, you ask?
Well, let me tell you.
Again, when the angles are mirrored like this, they do not change. We can see that the 90 degree angle also does not change. The length of YZ is 20 ft. To find WX, we simply need to multiply YZ by our scaling factor of 62.5%. Doing so will give us our answer of 12.5 ft.
The expressway is 12.5 feet from point W.
I hope that helped, and I _really_ hope I did that right! =P
