| 40 | ÷ | ( | 200 | + | x | ) | = | 3 | ÷ | 20 |
| Multiply both sides of the equation by: | ( | 200 | + | x | ) |
| 40 | = | 3 | ÷ | 20 | × | ( | 200 | + | x | ) |
| 40 | = | 3 | ÷ | 20 | × | 200 | + | 3 | ÷ | 20 | × | x |
| 40 | = | 30 | + | 3 20 | x |
| - | 3 20 | x | = | 30 | − | 40 |
| - | 3 20 | x | = | - | 10 |
| 10 | = | 3 20 | x |
3 20 | x | = | 10 |
| x | = | 10 | ÷ | 3 20 |
| = | 10 | × | 20 3 |
| x | = | 200 3 |
| x | = | 66.666667 |