| ( | 140 | × | 1 2 | A | ) | + | ( | 120 | × | 1 5 | A | ) | + | ( | 90 | × | 3 10 | A | ) | = | 126100 |
| 方程左边 = | 140 | × | 1 2 | A | + | ( | 120 | × | 1 5 | A | ) | + | ( | 90 | × | 3 10 | A | ) |
| = | 70 | A | + | ( | 120 | × | 1 5 | A | ) | + | ( | 90 | × | 3 10 | A | ) |
| = | 70 | A | + | 120 | × | 1 5 | A | + | ( | 90 | × | 3 10 | A | ) |
| = | 70 | A | + | 24 | A | + | ( | 90 | × | 3 10 | A | ) |
| = | 94 | A | + | ( | 90 | × | 3 10 | A | ) |
| = | 94 | A | + | 90 | × | 3 10 | A |
| = | 94 | A | + | 27 | A |
| = | 121 | A |
| 121 | A | = | 126100 |
| A | = | 126100 | ÷ | 121 |
| = | 126100 | × | 1 121 |
| A | = | 126100 121 |
| A | = | 1042.14876 |