If a plane travels 400 mph the first 1500 miles of a 3000 mile trip how fast would it have to fly to average 500 miles per hour?

What do you think? Post your work and your answer here, we'll be happy to look at it and guide you in getting the right answer, but as per site rules we won't do your homework for you, that would be doing you a great disservice.

It will probibly fall into the ocean because they forgot to fill it up.