| ( | 198 | − | x | ) | ÷ | 20 | = | ( | 285 | − | x | ) | ÷ | 30 |
| Left side of the equation = | 198 | × | 1 20 | − | x | × | 1 20 |
| = | 99 10 | − | x | × | 1 20 |
99 10 | − | 1 20 | x | = | ( | 285 | − | x | ) | ÷ | 30 |
| Right side of the equation = | 285 | × | 1 30 | − | x | × | 1 30 |
| = | 19 2 | − | x | × | 1 30 |
99 10 | − | 1 20 | x | = | 19 2 | − | 1 30 | x |
| - | 1 20 | x | + | 1 30 | x | = | 19 2 | − | 99 10 |
| - | 1 60 | x | = | 19 2 | − | 99 10 |
| - | 1 60 | x | = | - | 2 5 |
2 5 | = | 1 60 | x |
1 60 | x | = | 2 5 |
| x | = | 2 5 | ÷ | 1 60 |
| = | 2 5 | × | 60 |
| = | 2 | × | 12 |
| x | = | 24 |