Question

Each week, Rosario drives to an ice skating rink that is 120 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?

Answer 1

While going to the ice skating rink,
Rosario drives a distance of 55 miles in = 1 hour
Then
While going to the ice skating rink,
Rosario drives a distance of 120 miles in = (1/55) * 120                                                                                                          = 2.18 hours
The number of miles per hour Rosario averages while coming back home = x Total up and down time taken by Rosario = 2.75 hours
Then time taken by Rosario to come back
home from ice skating rink = (2.75 – 2.18) hours                                                      = 0.57 hours
Then we can write the equation as
 x = 120/0.57 miles/hour   
    = 210.53 miles/hour
So the average speed of Rosario while coming back home from ice skating rink is 210.53 miles per hour.