Yesterday it took Robert 3 hours to drive from City A to City B. Today it took Robert 2.5 hours to drive back from City В to City A along the same route. If he had saved 30 minutes in both trips, the speed for the round trip would be 80 miles per hour. What is the distance between city A and city B?  Select the correct option:
A) 90  B) 180  C) 150  D) 240  E) 300

Rationale: "2 d / 80 = 4.5 ( because time = 3 + 2.5 - 1 hrs ) = > d = 180 answer - b"
Answer: B