| ( | 900 | − | 400 | ) | Q | − | 910000 | = | ( | 900 | − | 460 | ) | Q | − | 660000 |
| 方程左边 = | 900 | Q | − | 400 | Q | − | 910000 |
| = | 500 | Q | − | 910000 |
| 500 | Q | − | 910000 | = | ( | 900 | − | 460 | ) | Q | − | 660000 |
| 方程右边 = | 900 | Q | − | 460 | Q | − | 660000 |
| = | 440 | Q | − | 660000 |
| 500 | Q | − | 910000 | = | 440 | Q | − | 660000 |
| 500 | Q | − | 440 | Q | = | - | 660000 | + | 910000 |
| 60 | Q | = | - | 660000 | + | 910000 |
| 60 | Q | = | 250000 |
| Q | = | 250000 | ÷ | 60 |
| = | 250000 | × | 1 60 |
| = | 12500 | × | 1 3 |
| Q | = | 12500 3 |
| Q | = | 4166.666667 |