| ( | 12 | − | p | ) | ÷ | 3 10 | = | ( | p | − | 1 | ) | ÷ | 1 2 |
| Left side of the equation = | 12 | × | 10 3 | − | p | × | 10 3 |
| = | 40 | − | p | × | 10 3 |
| 40 | − | 10 3 | p | = | ( | p | − | 1 | ) | ÷ | 1 2 |
| Right side of the equation = | p | × | 2 | − | 1 | × | 2 |
| = | p | × | 2 | − | 2 |
| 40 | − | 10 3 | p | = | 2 | p | − | 2 |
| - | 10 3 | p | − | 2 | p | = | - | 2 | − | 40 |
| - | 16 3 | p | = | - | 2 | − | 40 |
| - | 16 3 | p | = | - | 42 |
| 42 | = | 16 3 | p |
16 3 | p | = | 42 |
| p | = | 42 | ÷ | 16 3 |
| = | 42 | × | 3 16 |
| = | 21 | × | 3 8 |
| p | = | 63 8 |
| p | = | 7.875 |