| 90 | ( | 10000 | ÷ | x | ) | + | 110 | ( | 10000 | ÷ | 90 | − | 10000 | ÷ | x | ) | + | 90 | ( | 20000 | ÷ | x | − | 10000 | ÷ | 90 | ) | + | 110 | ( | 30000 | ÷ | x | − | 20000 | ÷ | x | ) | + | 130 | ( | 30000 | ÷ | x | ) | = | 20000 |
| 90 | × | 10000 | ÷ | x | + | 110 | ( | 10000 | ÷ | 90 | − | 10000 | ÷ | x | ) | + | 90 | ( | 20000 | ÷ | x | − | 10000 | ÷ | 90 | ) | + | 110 | ( | 30000 | ÷ | x | − | 20000 | ÷ | x | ) | + | 130 | ( | 30000 | ÷ | x | ) | = | 20000 |
| 900000 | ÷ | x | + | 110 | ( | 10000 | ÷ | 90 | − | 10000 | ÷ | x | ) | + | 90 | ( | 20000 | ÷ | x | − | 10000 | ÷ | 90 | ) | + | 110 | ( | 30000 | ÷ | x | − | 20000 | ÷ | x | ) | + | 130 | ( | 30000 | ÷ | x | ) | = | 20000 |
| Multiply both sides of the equation by: | x |
| 900000 | + | 110 | ( | 10000 | ÷ | 90 | − | 10000 | ÷ | x | ) | x | + | 90 | ( | 20000 | ÷ | x | − | 10000 | ÷ | 90 | ) | x | + | 110 | ( | 30000 | ÷ | x | − | 20000 | ÷ | x | ) | x | + | 130 | ( | 30000 | ÷ | 1 | ) | = | 20000 | x |
| 900000 | + | 110 | × | 10000 | ÷ | 90 | × | x | − | 110 | × | 10000 | ÷ | x | × | x | + | 90 | ( | 20000 | ÷ | x | − | 10000 | ÷ | 90 | ) | x | = | 20000 | x |
| 900000 | + | 110000 9 | x | − | 1100000 | ÷ | x | × | x | + | 90 | ( | 20000 | ÷ | x | − | 10000 | ÷ | 90 | ) | x | + | 110 | ( | 30000 | ÷ | x | − | 20000 | ÷ | x | ) | x | = | 20000 | x |
| 900000 | + | 110000 9 | x | − | 1100000 | ÷ | 1 | × | 1 | + | 90 | × | 20000 | ÷ | x | × | x | − | 90 | × | 10000 | = | 20000 | x |
| 900000 | + | 110000 9 | x | − | 1100000 | + | 1800000 | ÷ | x | × | x | − | 10000 | x | + | 110 | ( | 30000 | ÷ | x | − | 20000 | ÷ | x | ) | x | = | 20000 | x |
| - | 200000 | + | 20000 9 | x | + | 1800000 | ÷ | x | × | x | + | 110 | ( | 30000 | ÷ | x | − | 20000 | ÷ | x | ) | x | + | 130 | ( | 30000 | ÷ | 1 | ) | = | 20000 | x |
| - | 200000 | + | 20000 9 | x | + | 1800000 | ÷ | 1 | × | 1 | + | 110 | × | 30000 | ÷ | x | × | x | − | 110 | × | 20000 | = | 20000 | x |
| - | 200000 | + | 20000 9 | x | + | 1800000 | + | 3300000 | ÷ | x | × | x | − | 2200000 | ÷ | x | × | x | + | 130 | ( | 30000 | ÷ | 1 | ) | = | 20000 | x |
| 1600000 | + | 20000 9 | x | + | 3300000 | ÷ | x | × | x | − | 2200000 | ÷ | x | × | x | + | 130 | ( | 30000 | ÷ | 1 | ) | = | 20000 | x |
| 1600000 | + | 20000 9 | x | + | 3300000 | ÷ | 1 | × | 1 | − | 2200000 | ÷ | 1 | × | 1 | + | 130 | × | 30000 | ÷ | 1 | = | 20000 | x |
| 1600000 | + | 20000 9 | x | + | 3300000 | − | 2200000 | + | 3900000 | = | 20000 | x |
| 6600000 | + | 20000 9 | x | = | 20000 | x |
20000 9 | x | − | 20000 | x | = | - | 6600000 |
| - | 160000 9 | x | = | - | 6600000 |
| 6600000 | = | 160000 9 | x |
160000 9 | x | = | 6600000 |
| x | = | 6600000 | ÷ | 160000 9 |
| = | 6600000 | × | 9 160000 |
| = | 165 | × | 9 4 |
| x | = | 1485 4 |
| x | = | 371.25 |