| ( | a | × | 20 100 | + | a | ) | × | 20 100 | + | a | × | 20 100 | = | 171000 |
| Left side of the equation = | a | × | 20 100 | × | 20 100 | + | a | × | 20 100 | + | 20 100 | a |
| = | a | × | 1 25 | + | a | × | 20 100 | + | 20 100 | a |
| = | 11 25 | a |
11 25 | a | = | 171000 |
| a | = | 171000 | ÷ | 11 25 |
| = | 171000 | × | 25 11 |
| a | = | 4275000 11 |
| a | = | 388636.363636 |