Mathematics problems in the first volume of the first day of junior high school (more than ten courses)
1. It is known that x and y satisfy three conditions at the same time: 3x-2y=4-p, 4x-3y=2+p, x>y, and find the range of p (important process) 2. Pump the sewage accumulated in the sewage pipe with a pump that can pump 30 tons of water per minute. It is estimated that the accumulated sewage is between 1200 tons and 1500 tons, so how long will it take to pump out the sewage? Suppose it takes x minutes to finish pumping sewage, which can be expressed as: (expression) 3. A person's hair is about 654.38+ 10,000 to 200,000, and each hair grows about 0.32 32 mm per day. Xiaoying's hair is about 10cm long now, so how long will it take for her hair to grow to 16cm to 28cm? (important process) 4. Known inequality {2x-a