A. B is 80km away. A and B start from a to B. one hour after a starts, B catches up with a speed 1.5 times that of A. when B catches up with B, a arrives 20 minutes ahead of B. what's the speed of a and B?

A. B is 80km away. A and B start from a to B. one hour after a starts, B catches up with a speed 1.5 times that of A. when B catches up with B, a arrives 20 minutes ahead of B. what's the speed of a and B?

Suppose the speed of a is XKM / h, then the speed of B is 1.5xkm/h. According to the meaning of the question, we can get: 80x − 801.5x = 1 − 2060 solution: x = 40 test: substitute x = 40 into 3x ≠ 0, so x = 40 is the solution of the original equation, so the speed of B is: 1.5x = 60 (km / h) answer: the speed of a and B is 40km / h and 60km / h respectively

For a project, it takes 40 days for engineering team a to complete the task alone. Now engineering team B does it 30 days first, and the two teams cooperate 20 days to complete the task. How many days does engineering team B need to complete the task alone?

It takes X days for engineering team B to complete the task. The speed of team a is 140, and that of team B is 1 X. from the meaning of the question: 30x + 20 (140 + 1 x) = 1, the solution is: x = 100. It is tested that x = 100 is the root of the original equation. Answer: it takes 100 days for engineering team B to complete the task alone

On the application of fraction
1. If everyone's work efficiency is the same every day, and m people can make p parts in n days, how many days does it take for n people to make M parts
2. The two engineering teams a and B contract a project and stipulate half of the tasks to be completed. Team a starts to work on a certain day in March. Team B starts work four days later than team A. finally, team a completes its own task on April 22 and team B completes its task on April 24. If team a works for X days in total, please use the formula containing x to express the amount of tasks that team a and team B complete in March

1. If everyone's work efficiency is the same every day, and m people can make p parts in n days, then how many days does it take n people to make M parts? (how to do this? Please explain,!)
The workload per person per day is: P / (m × n)
So the day n people make M parts is: M / [P / (MN) × n] = m / (P / M) = m ^ 2 / P
2. The two engineering teams a and B contract a project and stipulate half of each task to be completed. Team a starts to work on a certain day in March, team B starts work four days later than team A. finally, team a completes its own task on April 22, and team B completes its task on April 24. If team a works for X days in total, please use the formula containing x to express the amount of tasks that team a and team B complete in March
According to the meaning of the title, B starts 4 days later than a and finishes 2 days later than a, which means that B works 2 days less than a, that is, X-2 days
A the number of days in March is: x-22, then the workload is: 1 / X * (x-22)
B the number of days in March is: (X-2) - 24 = x-26, then the workload is: 1 / (X-2) * (x-26)

Mr. Wang rides a bicycle on the ring road at a constant speed. Every six minutes, a bus around the lake runs backward from the opposite side. Every 30 minutes, another bus around the lake runs forward from the back. If the bus around the lake also runs at a constant speed, regardless of the time for passengers to get on and off the bus, then the starting point should be every two minutes______ A bus around the lake will leave in 30 minutes

Let's take a bus around the lake every X minutes. From the title, we can get: 30-x = 5 (X-6), 30-x = 5x-30, 6x = 60, x = 10; answer: take a bus around the lake every 10 minutes from the starting station