Two towns, A and B, are connected by a straight road, 30 miles long. Traveling from town A to town B, the speed limit changes: the first 10 miles are 40 mph, the next 10 miles are 60 mph, and the last 10 miles are 50 mph. Two cars, one starting from town A and one from town B, move toward each other at the same time. They adhere strictly to the speed limits in each section. How far from town A, in miles, will the two cars meet?