| Q | ( | 200 | − | 120 | ) | − | 100 | − | 500 | × | 5 100 | ( | 1 | − | 30 100 | ) | ÷ | 50 | = | 0 |
| Left side of the equation = | Q | ( | 200 | − | 120 | ) | − | 100 | − | 1 2 | ( | 1 | − | 30 100 | ) |
| Q | ( | 200 | − | 120 | ) | − | 100 | − | 1 2 | ( | 1 | − | 30 100 | ) | = | 0 |
| Left side of the equation = | Q | × | 200 | − | Q | × | 120 | − | 100 | − | 1 2 | ( | 1 | − | 30 100 | ) |
| = | 80 | Q | − | 100 | − | 1 2 | ( | 1 | − | 30 100 | ) |
| = | 80 | Q | − | 100 | − | 1 2 | × | 1 | + | 1 2 | × | 30 100 |
| = | 80 | Q | − | 100 | − | 1 2 | + | 3 20 |
| = | 80 | Q | − | 2007 20 |
| 80 | Q | − | 2007 20 | = | 0 |
| 80 | Q | = | 0 | + | 2007 20 |
| 80 | Q | = | 2007 20 |
| Q | = | 2007 20 | ÷ | 80 |
| = | 2007 20 | × | 1 80 |
| Q | = | 2007 1600 |
| Q | = | 1.254375 |