20 100 | W | + | 25 100 | ( | 1 | − | W | ) | = | 22 100 |
| 方程左边 = | 20 100 | W | + | 25 100 | × | 1 | − | 25 100 | W |
| = | 20 100 | W | + | 1 4 | − | 25 100 | W |
| = | - | 1 20 | W | + | 1 4 |
| - | 1 20 | W | + | 1 4 | = | 22 100 |
| - | 1 20 | W | = | 22 100 | − | 1 4 |
| - | 1 20 | W | = | - | 3 100 |
3 100 | = | 1 20 | W |
1 20 | W | = | 3 100 |
| W | = | 3 100 | ÷ | 1 20 |
| = | 3 100 | × | 20 |
| = | 3 5 | × | 1 |
| W | = | 3 5 |
| W | = | 0.6 |