If it takes 1 hour to go 40 miles, then if you multiply 40 by 3, ( 3 being the amount of hours ) you would have 120. ( the amount of miles it takes for Javier to get to his grandmother. ) So, because there is only a 2 hour difference between 7 AM and 9 AM, it would be unreasonable for Javier to be in his grandmothers city. But, it WILL be reasonable for Javier to be in his grandmothers city by 10 AM.