A rocket soars for 12 seconds at 150 meters per second. It then plummets 600 meters in 3 seconds. What is the average speed of the rocket in meters per second?  Choose the correct choice from the following choices.
A) 140  B) 150  C) 155  D) 160  E) 175

Rationale: when soaring , the rocket travels a total distance of 1800 m ( 150 m / s for 12 s ) while plummeting the rockets travel distance of 600 m in 3 s the total distance traveled is 2400 m ( 1800 + 600 ) the time taken to travel this distance is 15 s ( 12 + 3 ) average speed = 2400 / 15 = 160 ans : ( option d )
Answer: D