解：设一元硬币有x个，则五角硬币有（68-x）个。x+0.5（68-x）=55.5x+34-0.5x=55.50.5x=21.5x=43
设5角为X 一元为YX+Y=6855*5=X*5+Y*10Y=68-x555=X*5+(68-X)*10X=25Y=43
