11 20 | ( | 500 | − | X | ) | + | 200 | × | 11 20 | + | ( | X | − | 200 | ) | × | 3 5 | = | 581 2 |
| Left side of the equation = | 11 20 | ( | 500 | − | X | ) | + | 110 | + | ( | X | − | 200 | ) | × | 3 5 |
11 20 | ( | 500 | − | X | ) | + | 110 | + | ( | X | − | 200 | ) | × | 3 5 | = | 581 2 |
| Left side of the equation = | 11 20 | × | 500 | − | 11 20 | X | + | 110 | + | ( | X | − | 200 | ) | × | 3 5 |
| = | 275 | − | 11 20 | X | + | 110 | + | ( | X | − | 200 | ) | × | 3 5 |
| = | 385 | − | 11 20 | X | + | ( | X | − | 200 | ) | × | 3 5 |
| = | 385 | − | 11 20 | X | + | X | × | 3 5 | − | 200 | × | 3 5 |
| = | 385 | − | 11 20 | X | + | X | × | 3 5 | − | 120 |
| = | 265 | + | 1 20 | X |
| 265 | + | 1 20 | X | = | 581 2 |
1 20 | X | = | 581 2 | − | 265 |
1 20 | X | = | 51 2 |
| X | = | 51 2 | ÷ | 1 20 |
| = | 51 2 | × | 20 |
| = | 51 | × | 10 |
| X | = | 510 |