1 5 | = | ( | 100 | × | 4 5 | ) | ÷ | ( | 100 | + | x | ) |
| Multiply both sides of the equation by: | ( | 100 | + | x | ) |
1 5 | ( | 100 | + | x | ) | = | ( | 100 | × | 4 5 | ) |
1 5 | × | 100 | + | 1 5 | x | = | ( | 100 | × | 4 5 | ) |
1 5 | × | 100 | + | 1 5 | x | = | 100 | × | 4 5 |
| 20 | + | 1 5 | x | = | 80 |
1 5 | x | = | 80 | − | 20 |
1 5 | x | = | 60 |
| x | = | 60 | ÷ | 1 5 |
| = | 60 | × | 5 |
| x | = | 300 |