My aunt and I were approaching the same intersection, she from the south and I from the west.

My aunt and I were approaching the same intersection, she from the south and I from the west. She was traveling at a steady speed of 6 miles/hour, while I was approaching the intersection at 70 miles/hour. At a certain instant in time, I was one-tenth of a mile from the intersection, while she was three-twentieths of a mile from it. How fast were we approaching each other at that instant?