The railway from Beijing to Nanjing is about 1200 kilometers long. It takes 10 hours for the express train and 15 hours for the slow train. The two trains leave from both places at the same time and meet in a few hours

The railway from Beijing to Nanjing is about 1200 kilometers long. It takes 10 hours for the express train and 15 hours for the slow train. The two trains leave from both places at the same time and meet in a few hours

6 hours, 1200 divided by (1200 divided by 10 + 1200 divided by 15) = 6

The railway from Nanjing to Beijing is 1157 kilometers long. An express train departs from Nanjing to Beijing at 22:30, 68 kilometers per hour. At the same time, there is a slow train
From Beijing to Nanjing, it is known that the two trains met at 7:30 the next morning. How many kilometers per hour is the local train?

7: 30-22:30 + 24 = 9 hours
1157 / 9 = 128.56 km / h
128.56-68 = 50.56 km / h
Of course, it can also be solved by algebraic method. The principle is the same

A map of China at the scale of 1:6 million. The railway from Shanghai to Nanjing is 5 cm long. The express train runs from Shanghai to Nanjing at the speed of 60 km / h. how many hours does it take

The actual distance from Shanghai to Nanjing is x cm
5：X=1：600 0000
X=3000 0000
30000000 cm = 300km
60 / 300 = 5 hours