| ( | 1500 | + | x | ) | ÷ | 30 | = | ( | 1500 | − | 300 | ) | ÷ | 20 |
| Left side of the equation = | 1500 | × | 1 30 | + | x | × | 1 30 |
| = | 50 | + | x | × | 1 30 |
| 50 | + | 1 30 | x | = | ( | 1500 | − | 300 | ) | ÷ | 20 |
| Right side of the equation = | 1500 | × | 1 20 | − | 300 | × | 1 20 |
| = | 75 | − | 15 |
| = | 60 |
| 50 | + | 1 30 | x | = | 60 |
1 30 | x | = | 60 | − | 50 |
1 30 | x | = | 10 |
| x | = | 10 | ÷ | 1 30 |
| = | 10 | × | 30 |
| x | = | 300 |