Wendy Stasnick drives for a number of hours at 70 miles per hour. Road construction appears and traffic slows and she drives at 50 miles per hour. She travels at 50 miles per hour for .5 hours longer then she traveled at 70 miles per hour. The difference in the distance traveled at 50 miles per hour and 70 miles per hour is 5 miles. How long was Wendy driving at 50 miles per hour?