1) A short airplane trip between two cities took 30 minutes when traveling with the wind. The return trip took 45 minutes when traveling against the wind. If the speed of the plane with no wind is 320 mph, find the speed of the wind and the distance between the two cities (hint: pay attention to units).
2) One morning, Justin drove 3 hours before stopping to eat lunch. After lunch, he increased his speed by 10 mph. If he completed a 450-mile trip in 8 hours of driving time, how fast (in miles per hour) did he drive in the morning?
3) A high-speed train makes a 320 mile nonstop run between two major cities in 512 hours. The train travels 80 mph in the country, but safety regulations require that it travel only 20 mph when passing through smaller, intermediate cities. How many hours are spent traveling through the smaller cities?