| 403 | ÷ | 31 | × | x | + | 155 | ÷ | 31 | × | ( | x | + | 15 | ) | + | 93 | ÷ | 31 | × | ( | x | + | 30 | ) | = | 683 |
| Left side of the equation = | 13 | x | + | 5 | ( | x | + | 15 | ) | + | 3 | ( | x | + | 30 | ) |
| 13 | x | + | 5 | ( | x | + | 15 | ) | + | 3 | ( | x | + | 30 | ) | = | 683 |
| Left side of the equation = | 13 | x | + | 5 | x | + | 5 | × | 15 | + | 3 | ( | x | + | 30 | ) |
| = | 13 | x | + | 5 | x | + | 75 | + | 3 | ( | x | + | 30 | ) |
| = | 18 | x | + | 75 | + | 3 | ( | x | + | 30 | ) |
| = | 18 | x | + | 75 | + | 3 | x | + | 3 | × | 30 |
| = | 18 | x | + | 75 | + | 3 | x | + | 90 |
| = | 21 | x | + | 165 |
| 21 | x | + | 165 | = | 683 |
| 21 | x | = | 683 | − | 165 |
| 21 | x | = | 518 |
| x | = | 518 | ÷ | 21 |
| = | 518 | × | 1 21 |
| = | 74 | × | 1 3 |
| x | = | 74 3 |
| x | = | 24.666667 |