Description: Sal chooses equations that give a faster rate than the relationship given in a table. Created by Sal Khan. All right, which of the following equations, where x represents hours, and y represents miles, represents a speed that is greater than Maria and Nadia's speed? So if we wanted to figure out their speed, you would figure out distance divided by time. And assuming they went on a constant speed the whole time, they should have been going 60 miles per hour on day two as well.*Teacher Advisor is 100% free.