| 2 | × | 40 | X | × | 30 | = | 2 | × | 120 | ( | 50 | − | X | ) |
| Left side of the equation = | 2400 | X |
| 2400 | X | = | 2 | × | 120 | ( | 50 | − | X | ) |
| Right side of the equation = | 240 | ( | 50 | − | X | ) |
| 2400 | X | = | 240 | ( | 50 | − | X | ) |
| Right side of the equation = | 240 | × | 50 | − | 240 | X |
| = | 12000 | − | 240 | X |
| 2400 | X | = | 12000 | − | 240 | X |
| 2400 | X | + | 240 | X | = | 12000 |
| 2640 | X | = | 12000 |
| X | = | 12000 | ÷ | 2640 |
| = | 12000 | × | 1 2640 |
| = | 50 | × | 1 11 |
| X | = | 50 11 |
| X | = | 4.545455 |