| ( | 68 | − | 49 | ) | ÷ | ( | 49 | − | 40 | ) | = | ( | 85 | − | t | ) | ÷ | ( | t | − | 71 | ) |
| Multiply both sides of the equation by: | ( | 49 | − | 40 | ) | , | ( | t | − | 71 | ) |
| ( | 68 | − | 49 | ) | ( | t | − | 71 | ) | = | ( | 85 | − | t | ) | ( | 49 | − | 40 | ) |
| 68 | ( | t | − | 71 | ) | − | 49 | ( | t | − | 71 | ) | = | ( | 85 | − | t | ) | ( | 49 | − | 40 | ) |
| 68 | ( | t | − | 71 | ) | − | 49 | ( | t | − | 71 | ) | = | 85 | ( | 49 | − | 40 | ) | − | t | ( | 49 | − | 40 | ) |
| 68 | t | − | 68 | × | 71 | − | 49 | ( | t | − | 71 | ) | = | 85 | ( | 49 | − | 40 | ) | − | t | ( | 49 | − | 40 | ) |
| 68 | t | − | 68 | × | 71 | − | 49 | ( | t | − | 71 | ) | = | 85 | × | 49 | − | 85 | × | 40 | − | t | ( | 49 | − | 40 | ) |
| 68 | t | − | 4828 | − | 49 | ( | t | − | 71 | ) | = | 4165 | − | 3400 | − | t | ( | 49 | − | 40 | ) |
| 68 | t | − | 4828 | − | 49 | ( | t | − | 71 | ) | = | 765 | − | t | ( | 49 | − | 40 | ) |
| 68 | t | − | 4828 | − | 49 | t | + | 49 | × | 71 | = | 765 | − | t | ( | 49 | − | 40 | ) |
| 68 | t | − | 4828 | − | 49 | t | + | 49 | × | 71 | = | 765 | − | t | × | 49 | + | t | × | 40 |
| 68 | t | − | 4828 | − | 49 | t | + | 3479 | = | 765 | − | t | × | 49 | + | t | × | 40 |
| 19 | t | − | 1349 | = | 765 | − | 9 | t |
| 19 | t | + | 9 | t | = | 765 | + | 1349 |
| 28 | t | = | 765 | + | 1349 |
| 28 | t | = | 2114 |
| t | = | 2114 | ÷ | 28 |
| = | 2114 | × | 1 28 |
| = | 151 | × | 1 2 |
| t | = | 151 2 |
| t | = | 75.5 |