Solution #17

2 miles per minute is a speed of 120 miles per hour, and 2 minutes per mile is a speed of 30 miles per hour. Let d be the distance from A to B. Then the time in one direction is d/120, and in the other direction is d/30. This is a total travel time of 5d/120, and a total distance of 2d. The speed is thus 2d/(5d/120) = 240/5 = 48.