1. There is a wire. For the first time, less than half of it was used 1 m, and for the second time, half of it was used, and the remaining thread exceeded 1 m. As a result, there are still 2.5 meters left in the wire. How long is this wire? 2. Pour a bucket full of water in a cylindrical bucket with an internal diameter of 200mm into rectangular iron boxes with internal length \ width \ height of 300mm.300mm.80mm respectively, and fill them up. How high is the water in the cylindrical barrel? The train was blocked halfway, delayed for 6 minutes, and then the speed was increased from 40 kilometers to 50 kilometers per hour. How many kilometers can I make up for the delay? 4. A seventh-grade (1) class of a school organizes extracurricular activities, prepares to hold a badminton competition, and goes to the store to buy badminton rackets and shuttlecocks. 25 yuan for each racket, 2 yuan for each ball. Store A said "Badminton and racket are 10% off", while Store B said "Buy one racket and get two shuttlecocks. (1) The school is going to spend all the money from 90 yuan to buy two shuttlecocks. (2) If you have to buy two pairs of badminton rackets, how many pairs should you buy in two stores? Three students, A, B and C, donated books to children in poor areas. It is understood that the proportion of books donated by these three students is 5:6:9. If the sum of the books donated by two students, A, B and C, is twice as much as that donated by B, which is greater than 12, how many books did they donate respectively?

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1. Solution: This line was originally x meters long. x-[ 1/2( 1/2x- 1)+ 1]= 2.5x = 4 ^ 2。 Solution: the height is xmm100.100.л x.40x = 4 4. A: After 10% discount, the racket is: 22.5 yuan/ball is 1.8 yuan/racket is 22.5.2 = 45 yuan ball: (90-45)÷ 1.8=25 (only) B: 25.2 = 50 (yuan Party A can buy 25.2). Therefore, Party A is more cost-effective. 5. Solution: Each block is Xa: 5xb: 6xc: 9x5x+9x = 6x.2+12x = 6, so: A: 5.6 = 30 (Ben) B: 6.6.