| 1 | ( | t | − | 30 | ) | = | 7 | ( | 40 | − | t | ) |
| Left side of the equation = | 1 | t | − | 1 | × | 30 |
| = | 1 | t | − | 30 |
| 1 | t | − | 30 | = | 7 | ( | 40 | − | t | ) |
| Right side of the equation = | 7 | × | 40 | − | 7 | t |
| = | 280 | − | 7 | t |
| 1 | t | − | 30 | = | 280 | − | 7 | t |
| 1 | t | + | 7 | t | = | 280 | + | 30 |
| 8 | t | = | 280 | + | 30 |
| 8 | t | = | 310 |
| t | = | 310 | ÷ | 8 |
| = | 310 | × | 1 8 |
| = | 155 | × | 1 4 |
| t | = | 155 4 |
| t | = | 38.75 |