由x+ 5x = 5y得 6x = 5y;24x = 20y;由300 + 4x = 4y -100得400 + 4x = 4y;2000 + 20x = 20y;由24x = 20y 与2000 + 20x = 20y;得 24x = 2000 + 20x4x = 2000解得x = 500;再由x + 5x = 5y解得 y = 600;