Zhang Ming drives from city a to city B at the speed of 60 kilometers per hour. When he returns, he rides at the speed of 40 kilometers per hour What's the average speed of the motorcycle from city B to city a?

48 km / h

A car drives from city a to city B at the speed of 40 kilometers per hour. When it returns, it uses the original speed to drive 34 kilometers more than 5 kilometers, and then uses the speed of 30 kilometers per hour to complete the rest of the journey. Therefore, it takes 10 minutes more to return to city a than to go to city B. how far is the distance between city a and city B?

The distance between the two cities of Party A and Party B is x km, and the distance between the two cities of Party B and Party B is x km, 1-34 = 14, 10 minutes = 16 hours (14x-5) and 10 minutes = 16 hours (14x-5) and 30 - (14x-5) and (14x-5) and 30 - (14x-5) and (14x-5) and 10 minutes = 16 hours (14x-5) and 10 minutes = 16 hours (14x-5) and 30 - (14x-5-5) and (14x-5)) and 40 = 40 = 16 & nbsp & nbsp & nbsp; & nbsp; & nbsp; & nbsp; & nbsp; & nbsp; & nbsp; & nbsp; & nbsp; & nbsp; & nbsp; & nbsp; & nbsp; & nbsp; & nbsp; & nbsp; & nbsp; & nbsp; & nbsp; & nbsp; & nbsp; & nbsp; & nbsp; & nbsp; & nbsp; & nbsp; & nbsp; & nbsp; & nbsp; & nbsp; & nbsp; & nbsp; & nbsp; & nbsp; & nbsp; & nbsp; & nbsp; & nbsp; & nbsp; & nbsp; & nbsp; & nbsp; & nbsp; & nbsp; & nbsp; & nbsp; & nbsp; & nbsp& nbsp; & nbsp; & nbsp; &A: the distance between the two cities is 100 km

A car from a city to B city, 60 kilometers per hour, from B city back to a city, 90 kilometers per hour

72 km / h
The two cities are 180 kilometers apart
180 * 2 / (180 / 60 + 180 / 90) = 72 km / h

A car goes from place a to place B at 60 km / h for 3 hours. It goes back at 90 km / h?

60 × 3 = 180 (km), 180 ／ 90 = 2 (H), 180 × 2 ／ (3 + 2), = 360 ／ 5, = 72 (km / h), a: the average speed of this car is 72 km / h

Zhang Ming drives from city a to city B at the speed of 60 kilometers per hour. When he returns, he rides at the speed of 40 kilometers per hour What's the average speed of the motorcycle from city B to city a?