| ( | 50000 | ( | 1 | + | 15 100 | ) | + | y | ) | × | 5 100 | = | 50000 | × | 15 100 | + | 4000 |
| Left side of the equation = | 50000 | ( | 1 | + | 15 100 | ) | × | 5 100 | + | y | × | 5 100 |
| = | 2500 | ( | 1 | + | 15 100 | ) | + | y | × | 5 100 |
| = | 2500 | × | 1 | + | 2500 | × | 15 100 | + | 5 100 | y |
| = | 2500 | + | 375 | + | 5 100 | y |
| = | 2875 | + | 5 100 | y |
| 2875 | + | 5 100 | y | = | 50000 | × | 15 100 | + | 4000 |
| Right side of the equation = | 7500 | + | 4000 |
| = | 11500 |
| 2875 | + | 5 100 | y | = | 11500 |
5 100 | y | = | 11500 | − | 2875 |
5 100 | y | = | 8625 |
| y | = | 8625 | ÷ | 5 100 |
| = | 8625 | × | 100 5 |
| = | 1725 | × | 100 |
| y | = | 172500 |