| 15 | = | 1 | ÷ | ( | 1 | + | r | ) | + | 1 | ÷ | ( | 1 | + | r | ) | × | 2 | + | 1 | ÷ | ( | 1 | + | r | ) | × | 3 | + | 1 | ÷ | ( | 1 | + | r | ) | × | 4 | + | ( | 1 | + | 16 | ) |
| Multiply both sides of the equation by: | ( | 1 | + | r | ) |
| 15 | ( | 1 | + | r | ) | = | 1 | + | 1 | × | 2 | + | 1 | × | 3 | + | 1 | × | 4 | + | ( | 1 | + | 16 | ) | × | 5 |
| 15 | × | 1 | + | 15 | r | = | 1 | + | 1 | × | 2 | + | 1 | × | 3 | + | 1 | × | 4 | + | ( | 1 | + | 16 | ) | × | 5 |
| 15 | × | 1 | + | 15 | r | = | 1 | + | 1 | × | 2 | + | 1 | × | 3 | + | 1 | × | 4 | + | 1 | × | 5 | + | 16 | × | 5 |
| 15 | + | 15 | r | = | 1 | + | 2 | + | 3 | + | 4 | + | 5 | + | 80 |
| 15 | + | 15 | r | = | 95 |
| 15 | r | = | 95 | − | 15 |
| 15 | r | = | 80 |
| r | = | 80 | ÷ | 15 |
| = | 80 | × | 1 15 |
| = | 16 | × | 1 3 |
| r | = | 16 3 |
| r | = | 5.333333 |