Yochana walked from home to the bus stop at an average speed of 5 mph. He immediately got on his school bus and traveld at an average speed of 60 mph until he got to school. The total distance from his home to school is 35 miles, and the entire trip took 1.5 hours. The following system of equations represents this: 5x + 60y = 35 and x + y = 1.5 Yochanan walked how many miles?