| ( | ( | 1 | + | 30 100 | ) | X | + | ( | 1 | + | 20 100 | ) | ( | 250 | − | X | ) | ) | × | 90 100 | = | 250 | + | 67 2 |
| Left side of the equation = | ( | 1 | + | 30 100 | ) | X | × | 90 100 | + | ( | 1 | + | 20 100 | ) | ( | 250 | − | X | ) | × | 90 100 |
| = | 1 | X | × | 90 100 | + | 30 100 | X | × | 90 100 | + | ( | 1 | + | 20 100 | ) | ( | 250 | − | X | ) | × | 90 100 |
| = | 9 10 | X | + | 27 100 | X | + | ( | 1 | + | 20 100 | ) | ( | 250 | − | X | ) | × | 90 100 |
| = | 117 100 | X | + | ( | 1 | + | 20 100 | ) | ( | 250 | − | X | ) | × | 90 100 |
| = | 117 100 | X | + | 1 | ( | 250 | − | X | ) | × | 90 100 | + | 20 100 | ( | 250 | − | X | ) | × | 90 100 |
| = | 117 100 | X | + | 9 10 | ( | 250 | − | X | ) | + | 9 50 | ( | 250 | − | X | ) |
| = | 117 100 | X | + | 9 10 | × | 250 | − | 9 10 | X | + | 9 50 | ( | 250 | − | X | ) |
| = | 117 100 | X | + | 225 | − | 9 10 | X | + | 9 50 | ( | 250 | − | X | ) |
| = | 27 100 | X | + | 225 | + | 9 50 | ( | 250 | − | X | ) |
| = | 27 100 | X | + | 225 | + | 9 50 | × | 250 | − | 9 50 | X |
| = | 27 100 | X | + | 225 | + | 45 | − | 9 50 | X |
| = | 9 100 | X | + | 270 |
9 100 | X | + | 270 | = | 250 | + | 67 2 |
| Right side of the equation = | 567 2 |
9 100 | X | + | 270 | = | 567 2 |
9 100 | X | = | 567 2 | − | 270 |
9 100 | X | = | 27 2 |
| X | = | 27 2 | ÷ | 9 100 |
| = | 27 2 | × | 100 9 |
| = | 3 | × | 50 |
| X | = | 150 |