A walks 20 meters per hour, B walks 30 meters per hour, C walks 40 meters per hour. Now a, B, C walks 300 meters at the same time. How many meters do a, B, C walk?

A300 × 20 / (20 + 30 + 40) = 300 × 2 / 9 = 200 / 3M
B300 × 30 / (20 + 30 + 40) = 300 × 1 / 3 = 100m
C300 × 40 / (20 + 30 + 40) = 300 × 4 / 9 = 400 / 3M

Two engineering teams build the same road. The first engineering team builds 250 meters a day. After 1000 meters, the second engineering team starts to build 200 meters a day. How many days after the second engineering team builds the same road, the two engineering teams build the same number of meters? (I want the teacher to answer)

The second engineering team is slower than the first engineering team in building roads. It will never catch up with the first engineering team. There is something wrong with your subject
The solution is as follows
Let X days later, the meters of the two projects are equal
1000+250X=200X
200 is not right. Let's take a look at the topic

The length ratio of the repaired road to the unmodified road is 1:3. After another 300 meters, the length ratio of the repaired road to the unmodified road is 1:2

300 / [1 / (1 + 2) - 1 / (1 + 3)] = 3600m
/It's divided by

An engineering team built a road of 600 meters in the first day, 20% of the total length in the second day, and 1 / 2 of the total length in two days?
It is necessary to have an answer today!

600÷（1/2-20%）
=600÷0.3
=2000 meters
Meet this type of problem can draw line diagram

A walks 20 meters per hour, B walks 30 meters per hour, C walks 40 meters per hour. Now a, B, C walks 300 meters at the same time. How many meters do a, B, C walk?