You need to go from point A to point B, and then back to point A. Points A and B are 20 miles apart. You go to point B at a constant speed of 15 miles per hour. If you want your overall speed to be 30 miles per hour, how fast would you have to go from point B back to point A?
You guys are over complicating things. Think of it as a simple grade 6 math averaging equation. Which speed from ba would make the overall or average speed 30mph.
15(mph) + 45(mph) = 60.
60/2 = 30 mph

Posted by alex
on 20041010 17:56:08 