| ( | 1 | ÷ | 15 | + | 1 | ÷ | 12 | ) | × | 3 | + | 1 | ÷ | 12 | × | X | = | 1 |
| Left side of the equation = | ( | 1 | ÷ | 15 | + | 1 | ÷ | 12 | ) | × | 3 | + | 1 12 | X |
| ( | 1 | ÷ | 15 | + | 1 | ÷ | 12 | ) | × | 3 | + | 1 12 | X | = | 1 |
| Left side of the equation = | 1 | ÷ | 15 | × | 3 | + | 1 | ÷ | 12 | × | 3 | + | 1 12 | X |
| = | 1 5 | + | 1 4 | + | 1 12 | X |
| = | 9 20 | + | 1 12 | X |
9 20 | + | 1 12 | X | = | 1 |
1 12 | X | = | 1 | − | 9 20 |
1 12 | X | = | 11 20 |
| X | = | 11 20 | ÷ | 1 12 |
| = | 11 20 | × | 12 |
| = | 11 5 | × | 3 |
| X | = | 33 5 |
| X | = | 6.6 |