A driver goes on a trip of 50 kilometers, the first 25 kilometers at 66 kilometers per hour and the remaining distance at 33 kilometers per hour. What is the average speed of the entire trip in kilometers per hour?  Choose the most appropriate option.
A) 38 B) 40 C) 44 D) 45 E) 48

Rationale: the time for the first part of the trip was 25 / 66 hours . the time for the second part of the trip was 25 / 33 hours . the total time fro the trip was 25 / 66 + 25 / 33 = 75 / 66 = 25 / 22 hours . the average speed for the trip was 50 / ( 25 / 22 ) = 44 kph the answer is c .
Answer: C