| 60 | ÷ | 20 | × | ( | 30 | + | t | ) | = | 80 | ÷ | 40 | × | t |
| Left side of the equation = | 3 | ( | 30 | + | t | ) |
| 3 | ( | 30 | + | t | ) | = | 80 | ÷ | 40 | × | t |
| Left side of the equation = | 3 | × | 30 | + | 3 | t |
| = | 90 | + | 3 | t |
| 90 | + | 3 | t | = | 80 | ÷ | 40 | × | t |
| Right side of the equation = | 2 | t |
| 90 | + | 3 | t | = | 2 | t |
| 3 | t | − | 2 | t | = | - | 90 |
| t | = | - | 90 |
| t | = | - | 90 |