| 15 | | 15 | | | 15 | 8% | | 21% | | | | 30 | 3000 | 55 40 | 30 55 | 25 | 25 | 3000 6000 55 | 6000 20% = 1200 | | 25 | | 3000 + 6000 ÷ 2 = 4500 | 25 4500 8% | 25 12 | = 108000 1200 | 108000 ÷ 120 = 900 55 | 1200 + 900 = 2100 | | 900 1200 | | | | | | | | | | |