A train from place a to place B runs 4 / 7 of the whole journey in 5 hours. At this speed, it takes several hours to complete the whole journey

A train from place a to place B runs 4 / 7 of the whole journey in 5 hours. At this speed, it takes several hours to complete the whole journey

The whole journey of the train is regarded as a whole,
4 / 7 in 5 hours,
4/7 / 5 = 4/35
It's 4 / 35 an hour,
1 / 4/35 = 35 / 4 = 8 + 3/4 = 8 + 45/60
It's eight hours and 45 minutes,
It's been driving for five hours,
The rest is three hours and 45 minutes

A train from a to B, 6.25 hours of 500 kilometers, just 5 / 8 of the whole line, according to this speed, how many hours to B
There's another way

5 / 8-6.25 = 10-6.25 = 3.75 hours
500 △ 5 / 8 = 800m
Speed 500 △ 6.25 = 80 km / h
And 800 △ 80-6.25 = 3.75 hours

The train goes from station a to station B in three hours, 6 / 11 of the whole journey
There are several more questions, please see
3. To unload a batch of goods, it was originally planned that 50 people would take part in it and finish it in 6 hours. Then, more workers were added. As a result, it was finished one hour ahead of schedule. How many more workers have been added?
6. Red Star harvester factory, in order to support dragon busy, seized the time to manufacture 140 small harvesters, 84 of which were manufactured in the first three days. According to this calculation, how many days will it take to complete the rest?
7. Red Star harvester factory manufactures a batch of small harvesters. Originally, it planned to manufacture 80 sets every day, and the task can be completed in 15 days. In fact, it has manufactured 20 more sets every day. At the present speed, how many days ahead of schedule can the task of manufacturing these small harvesters be completed?

If the speed is constant, the distance is proportional to the time, use the proportional example solution. (1-6 / 11): x = 6 / 11:3, x = 2.53, the total amount of goods is constant, the number of participants is inversely proportional to the working time, use the inverse example solution. (50 + x) * (6-1) = 50 * 6, x = 106, the work efficiency is constant, the total amount of work is positively proportional to the working time, use the proportional example solution. (140-84

A car from a to B, about 80 kilometers per hour, took 5 hours, only 4 hours to return. What is the speed of the car when it returns

80 × 5 / 4 = 400 / 4 = 100 (km / h) a: this car returns at a speed of 100 km / h