One-dimensional linear equation in junior one mathematics problem

1: Assume that the rest will take x hours to complete. Take a job as an integer 1. )

Solution: (4+X)/20+X/ 12= 1 Multiply both sides by 60:

12+3X+5X=60 8X=48 X=6 hours A: The rest will take 6 hours to complete.

2: (1700 = 0. 17000 yuan, 1300 = 0. 13000 yuan. )

Setup: tent a has x roof, and tent b has (600-X) roof.

Solution: 0.17x+0.13 (600-x) = 940.17x+78-0.13x = 94.

0.04X= 16 X=400 tops (A) 600-400=200 tops (b)

Checking calculation: 400× 0.17 = 680,000 yuan; 200× 0.13 = 260,000 yuan.

68+26 = 940,000 yuan.

A:A has 400 tents and B has 200 tents. ..

3: A: 40×5=200 yuan (buy 5 rackets and 5 boxes of balls);

B: (40+10) × 5× 0.9 = 250× 0.9 = 225 yuan.

225-200=25 yuan A is better than B in 25 yuan.