Doesn’t matter how darn long it took.
I think it does matter. To average 30mph the trip will take 4 minutes. You can go 100mph part of the trip and 10 mph some of it and 33mph some of it or 80mph some of it but the given is that you must average 30mph the whole trip. That is 4 minutes maximum allowed to make that 30mph average. You’ve used up 4 minutes going the first mile. No time left unless you can make it to the bottom of the hill instantaneously.
See #87