Each week, Rosario drives to an ice skating rink that is 60 miles away. The round-trip takes 2.75 hours. If he averages 55 miles per hour on his way to the rink, which equation can be used to find x, the number of miles per hour he averages on his way home?

WE know that (distance) = Speed * time

and Speed = distance/time & time = distance/speed

Let AB = 60 mi. & the speed is 55 mi/h, then the spent to reach the rink is

t = 60/55 = 1.09 h

Since the total time is 2.75 h & he spent 1.09h to go to the rink, so the time spent on his way back is 2.75-1.09 = 1.659 h

So his speed on his way back is 60/1.659 = 36.16 mi/h