| 2000 | = | 150 | ÷ | r | + | 2150 | ÷ | ( | r | r | ) |
| Multiply both sides of the equation by: | r |
| 2000 | r | = | 150 | + | 2150 | ÷ | ( | r | r | ) | × | r |
| Multiply both sides of the equation by: | ( | 1 | r | ) |
| 2000 | r | ( | 1 | r | ) | = | 150 | ( | 1 | r | ) | + | 2150 | × | 1 |
| 2000 | r | × | 1 | r | = | 150 | ( | 1 | r | ) | + | 2150 | × | 1 |
| 2000 | r | × | 1 | r | = | 150 | × | 1 | r | + | 2150 | × | 1 |
| 2000 | r | r | = | 150 | r | + | 2150 |
| r2= | 43 40 |