Question 41153
Average speed is (change in distance)/(change in time)
The distance is 440 miles 
The first part of the trip took 220/70 hours or 3.143 hours
The second part of the trip took 220/58 hours or 3.793 hours
Ave. Speed = 440 / (3.143 + 3.793) 
Ave. Speed = 440/6.936
Ave. Speed = 63.436 miles per hour