What was his average speed for the whole trip ?

　　In traveling from city A to city B, John drove for 1 hour at 50 mph and for 3 hours at 60 mph. What was his average speed for the whole trip ?　　53.5 &#821

　　In traveling from city A to city B, John drove for 1 hour at 50 mph and for 3 hours at 60 mph. What was his average speed for the whole trip ?

　　53.5 – 55 – 56 – 57.5

答案：57.5，这是一道简单的数学题，我们用题目给的条件求出A城到B城的总距离，在除以4个小时就可以得到正确答案了。