Originally Posted by F.R.O.G.
You're going to get a lot of people swearing that the correct answer is 90.
The fact it, it's a physical impossibility (although since you can accelerate instantaneously, anything might be possible). Now for people to figure out why.
OK, since everyone has figured it out.
HOLY COW I JUST LOOKED AT ALL THE POSTS!!!!!
You would need a Star Trek Teleporter at the 1/2 way point since all the available time to average 60 MPH was used up getting to the half way point at 30 MPH.
Assume a 2 mile track to keep it simple.
At 30 MPH traveling 1 mile takes 1/30th of an hour or 2 minutes
To average 60 MPH for 2 miles takes 2/60th of an hour or 2 minutes
Since the 2 minutes have already been driven, it is impossible to drive fast enough to drive the last mile in zero minutes.
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