3 10 | ( | 200 | ( | x | − | 1 20 | ) | + | 500 | ) | = | 180 |
| Left side of the equation = | 3 10 | × | 200 | ( | x | − | 1 20 | ) | + | 3 10 | × | 500 |
| = | 60 | ( | x | − | 1 20 | ) | + | 150 |
| = | 60 | x | − | 60 | × | 1 20 | + | 150 |
| = | 60 | x | − | 3 | + | 150 |
| = | 60 | x | + | 147 |
| 60 | x | + | 147 | = | 180 |
| 60 | x | = | 180 | − | 147 |
| 60 | x | = | 33 |
| x | = | 33 | ÷ | 60 |
| = | 33 | × | 1 60 |
| = | 11 | × | 1 20 |
| x | = | 11 20 |
| x | = | 0.55 |