Gwen drove an average speed of 15 miles per hour for the first 40 miles of a tripthen at a average speed of 30 miles/hr for the remaining 40 miles of the trip if she made no stops during the trip what was Gwen's avg speed in miles/hr for the entire trip	Choose the correct choice from the following answers:
A) 35 B) 20 C) 45 D) 50 E) 55

Rationale: avg . speed = total distance / total time total distance = 80 miles total time = 40 / 15 + 40 / 30 = 4 avg . speed = 20 . answer - b
Answer: B