Answer:
425 miles
Step-by-step explanation:
Their speed of closure is the sum of their speeds: 85 + 70 = 155 miles per hour. Then they cover the 775 mile distance in
... (775 mi)/(155 mi/h) = 5 h
Stephanie has traveled (85 mi/h)·(5 h) = 425 mi from Springfield to their meeting point in that time.