First, we need to figure out how long it took for the downhill path. If he goes down 3 times faster, it would be 3 times faster. So 30 divided by 3 is 10, then 30 + 10 is 40. He took 40 minutes. It must have been 4 miles to the place, because 8 divided by 2 is 4.There and back must have been 8 miles, and it took him 40 minutes, or 2/3 of an hour. If 8 is 2/3, then it was I think his average was 12 mph.