In order to protect the ecological balance and green the environment, the state strongly encourages "returning farmland to forest and grass", and its compensation policy is shown in table (1). A farmer in Danjiangkou reservoir area actively responds to the call of "one river to send spring water to Beijing" put forward by our city to cooperate with the national "south to North Water Diversion" project, and undertakes to plant trees and grass on a hillside, and the compensation obtained by the state is shown in table (2) How many mu of trees and grass?

In order to protect the ecological balance and green the environment, the state strongly encourages "returning farmland to forest and grass", and its compensation policy is shown in table (1). A farmer in Danjiangkou reservoir area actively responds to the call of "one river to send spring water to Beijing" put forward by our city to cooperate with the national "south to North Water Diversion" project, and undertakes to plant trees and grass on a hillside, and the compensation obtained by the state is shown in table (2) How many mu of trees and grass?

Let the farmer plant trees x mu, grass y mu, then x + y = 30150x + 100y = 4000, the solution is x = 20Y = 10

A transport team delivered a batch of goods in 20 days. In fact, it delivered 5 tons more per day. As a result, it not only finished 2 days in advance, but also transported 10 tons more. How many tons of this batch of goods? How many tons were originally planned to be transported every day?

Suppose this batch of goods has x tons, then (x + 10) tons are actually transported. From the question meaning: X20 = x + 1018 − 5. The solution is: x = 800. It is tested that x = 800 is the solution of the original equation. X20 = 40 answer: 800 tons of goods are transported, 40 tons per day

On the quadratic equation of two variables
1. There is a batch of clothes with a cost price of 100 yuan. If you want to make a profit of 30 to 60 yuan for each piece of clothing, please design a qualified and manned sales plan and calculate the actual profit of each piece of clothing in the plan_______________________
2. If the speed of a ship in still water is 10km per hour and the speed of water flow is 2km per hour, the speed of a ship in adverse water is 10km_______ What's the speed in downstream_________ .

Question 1: if the price is 200 yuan, give a 6.5% to 8% discount
Question 2: what's the speed of a ship sailing against the water_ 10-2=8km/h______ What's the speed in downstream__ 10+2=12km/h_______ .