| ( | X | + | 15 | ) | ÷ | 85 | − | X | ÷ | 100 | = | 6 25 |
| Left side of the equation = | X | × | 1 85 | + | 15 | × | 1 85 | − | 1 100 | X |
| = | X | × | 1 85 | + | 3 17 | − | 1 100 | X |
| = | 3 1700 | X | + | 3 17 |
3 1700 | X | + | 3 17 | = | 6 25 |
3 1700 | X | = | 6 25 | − | 3 17 |
3 1700 | X | = | 27 425 |
| X | = | 27 425 | ÷ | 3 1700 |
| = | 27 425 | × | 1700 3 |
| = | 9 | × | 4 |
| X | = | 36 |