Known to do some work, a to a day to complete, B to B days to complete, how many days to complete the cooperation between the two?

Known to do some work, a to a day to complete, B to B days to complete, how many days to complete the cooperation between the two?

A completes 1 / a every day, B completes 1 / B every day
Cooperate to complete 1 / A + 1 / b = (a + b) / AB every day
It takes AB / (a + b) days

1. There are 26 workers in the workshop who produce part a and Part B. each worker produces 120 parts A and 180 parts B on average every day. In order to match part a and part B according to 3:2, how many workers need to be allocated to produce part a and part B?
2. The train route of a and B is 40 km longer than the car route. The car leaves from a place with a speed of 40 km / h. After 0.5 hours, the train also leaves from a place with a speed of 60 km / h. as a result, the car arrives at B place one hour later than the train. Q: how many kilometers are the fire route and the car route of a and B?
3. My father said: "last year, the peanut yield of our two farmlands was 470kg, but the weather is not beautiful. There are droughts everywhere. This year, the two farmlands only produce 57kg of peanuts."
"This year, the output of the first field is 80% lower than that of last year, and the output of the second field is 90% lower than that of last year," the son said
Q: how many kilos of peanuts did the farmer produce in the two fields this year?

Suppose the number of workers producing part a and part B is x and Y respectively
From the meaning of the title: x + y = 26
120x:180y=3:2
The solution is x = 18, y = 8
2. The length of train road and car road is x and Y kilometers respectively
It can be seen from the meaning of the title: X-Y = 40
x/60+1=(y-0.5*40)/40
The solution is x = 300, y = 260
The yield of peanut in two fields is x kg and Y kg respectively
From the meaning of the title, we can see: x + y = 57
x/(1-80%)+y/(1-90%)=470
The solution is x = 20, y = 37

1 yuan twice applied questions
In the four corners of a square material, cut out a small square that becomes 1 cm in length, and fold the rest into a box with a volume of 128 cubic cm to calculate the side length of the original square material

Let the side length of the square material be x, then the bottom length of the box is X-2 and the height is 2
The volume is (X-2) ^ 2 * 2 = 128
x=10
The side length of the square material is 10 cm