| ( | x | − | 30 | ) | ( | 1 | − | 30 100 | ) | ÷ | 400 | = | ( | x | − | 40 | ) | ( | 1 | − | 20 100 | ) | ÷ | 200 |
| Left side of the equation = | x | ( | 1 | − | 30 100 | ) | × | 1 400 | − | 30 | ( | 1 | − | 30 100 | ) | × | 1 400 |
| = | x | ( | 1 | − | 30 100 | ) | × | 1 400 | − | 3 40 | ( | 1 | − | 30 100 | ) |
| = | x | × | 1 | × | 1 400 | − | x | × | 30 100 | × | 1 400 | − | 3 40 | ( | 1 | − | 30 100 | ) |
| = | x | × | 1 400 | − | x | × | 3 4000 | − | 3 40 | ( | 1 | − | 30 100 | ) |
| = | 7 4000 | x | − | 3 40 | ( | 1 | − | 30 100 | ) |
| = | 7 4000 | x | − | 3 40 | × | 1 | + | 3 40 | × | 30 100 |
| = | 7 4000 | x | − | 3 40 | + | 9 400 |
| = | 7 4000 | x | − | 21 400 |
7 4000 | x | − | 21 400 | = | ( | x | − | 40 | ) | ( | 1 | − | 20 100 | ) | ÷ | 200 |
| Right side of the equation = | x | ( | 1 | − | 20 100 | ) | × | 1 200 | − | 40 | ( | 1 | − | 20 100 | ) | × | 1 200 |
| = | x | ( | 1 | − | 20 100 | ) | × | 1 200 | − | 1 5 | ( | 1 | − | 20 100 | ) |
| = | x | × | 1 | × | 1 200 | − | x | × | 20 100 | × | 1 200 | − | 1 5 | ( | 1 | − | 20 100 | ) |
| = | x | × | 1 200 | − | x | × | 1 1000 | − | 1 5 | ( | 1 | − | 20 100 | ) |
| = | 1 250 | x | − | 1 5 | ( | 1 | − | 20 100 | ) |
| = | 1 250 | x | − | 1 5 | × | 1 | + | 1 5 | × | 20 100 |
| = | 1 250 | x | − | 1 5 | + | 1 25 |
| = | 1 250 | x | − | 4 25 |
7 4000 | x | − | 21 400 | = | 1 250 | x | − | 4 25 |
7 4000 | x | − | 1 250 | x | = | - | 4 25 | + | 21 400 |
| - | 9 4000 | x | = | - | 4 25 | + | 21 400 |
| - | 9 4000 | x | = | - | 43 400 |
43 400 | = | 9 4000 | x |
9 4000 | x | = | 43 400 |
| x | = | 43 400 | ÷ | 9 4000 |
| = | 43 400 | × | 4000 9 |
| = | 43 | × | 10 9 |
| x | = | 430 9 |
| x | = | 47.777778 |