| ( | X | + | 60 | ) | ÷ | ( | X | + | 100 | ) | = | 17 20 |
| Multiply both sides of the equation by: | ( | X | + | 100 | ) |
| ( | X | + | 60 | ) | = | 17 20 | ( | X | + | 100 | ) |
| X | + | 60 | = | 17 20 | ( | X | + | 100 | ) |
| X | + | 60 | = | 17 20 | X | + | 17 20 | × | 100 |
| X | + | 60 | = | 17 20 | X | + | 85 |
| X | − | 17 20 | X | = | 85 | − | 60 |
3 20 | X | = | 85 | − | 60 |
3 20 | X | = | 25 |
| X | = | 25 | ÷ | 3 20 |
| = | 25 | × | 20 3 |
| X | = | 500 3 |
| X | = | 166.666667 |