Equation is an effective model to depict the quantitative relationship in the real world. Please write an answer to the binary linear equations in combination with your actual life, and make the listed binary linear equations {x = 2Y, {x + y = 60

Equation is an effective model to depict the quantitative relationship in the real world. Please write an answer to the binary linear equations in combination with your actual life, and make the listed binary linear equations {x = 2Y, {x + y = 60

The school has some basketball and volleyball, a total of 60. The number of basketball is twice that of volleyball
Suppose there are x in volleyball and Y in basketball
x=2y
x+y=60
Solution
x=40
y=20

Six equation problems
1. A group of students from a to B, the speed is 8km per hour, when the road is 2km, the correspondent was ordered to go back to a to pick up things, he went back to a at 10km per hour to pick up things, immediately at the same speed to catch up with the team, the result is 3km away from B to catch up with the team, to find the distance between a and B (take things regardless of time)
2. Party A and Party B move forward from a and B at the same time at an average speed. The first time they meet is 700m away from a, and then they continue to move forward. When Party A arrives at B, and Party B arrives at a, they return immediately. The second time they meet is 400m away from B, and the distance between a and B is calculated
3. The ratio of three sides of a triangle is 2:4:5. The longest side is 6cm longer than the shortest side. Find the perimeter of the triangle
4. A company borrows 400000 yuan from the bank to develop a new product. It is known that the annual interest rate of the loan is 15% (excluding compound interest). The cost of each new product is 2.3 yuan, the selling price is 4 yuan, and the tax payable is 10% of the sales. If 200000 products are produced every year and the profit is used to repay the loan, how many years will it take to pay off? (profit = sales cost tax)
5. A greening team needs to plant some saplings along one side of a road, the first one is planted at the beginning of the road, and then one is planted every 5m, just one can be planted at the end of the road, so there are 21 saplings missing; if one tree is planted every 5.5m, just one can be planted at the end of the road, so there is only one sapling missing, so the number of saplings and the length of the road can be calculated
6. Xiao Ming rides a motorcycle from home to the railway station. If he travels 30km per hour, he will be 15 minutes earlier than the train. If he travels 18km per hour, he will be 15 minutes later than the train. Now Xiao Ming plans to arrive at the railway station 10 minutes before the train. What's the speed of his motorcycle?
It is suggested that if the direct unknowns are set, that is, when the train arrives at the railway station 10 minutes before the train starts, the speed of Xiaoming's motorcycle should be XKM / h, but it is difficult to formulate the equation, so the indirect unknowns can be considered

1. Suppose the distance XKM (x-3) / 8 = (x-3 + 2) / 10, and the solution is: x = 112. Suppose the velocity of a is x, the velocity of B is y, and the distance is Z

According to the equation x / 4 + X / 5 = 1, try to work out a practical problem. The content is related to our daily life and study~

For a project, it takes 4 months for Party A to do it alone, 5 months for Party B to do it alone, and how many months for Party A and Party B to do it together?