Susan drove an average speed of 15 miles per hour for the first 40 miles of a tripthen at a average speed of 60 miles/hr for the remaining 20 miles of the trip if she made no stops during the trip what was susan'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 = 60 miles total time = 40 / 15 + 20 / 60 = 3 avg . speed = 20 . answer - b
Answer: B