| 4 | ( | 1 | ÷ | 10 | + | 1 | ÷ | 15 | ) | + | 1 | ÷ | 15 | × | x | = | 1 |
| Left side of the equation = | 4 | ( | 1 | ÷ | 10 | + | 1 | ÷ | 15 | ) | + | 1 15 | x |
| 4 | ( | 1 | ÷ | 10 | + | 1 | ÷ | 15 | ) | + | 1 15 | x | = | 1 |
| Left side of the equation = | 4 | × | 1 | ÷ | 10 | + | 4 | × | 1 | ÷ | 15 | + | 1 15 | x |
| = | 2 5 | + | 4 15 | + | 1 15 | x |
| = | 2 3 | + | 1 15 | x |
2 3 | + | 1 15 | x | = | 1 |
1 15 | x | = | 1 | − | 2 3 |
1 15 | x | = | 1 3 |
| x | = | 1 3 | ÷ | 1 15 |
| = | 1 3 | × | 15 |
| = | 1 | × | 5 |
| x | = | 5 |