写出解答问题所需要的直接条件.平均每人每小时做多少个零件? .
0.75=12÷ = :12== %= 折.
0.75=12÷ =9: = %
0.7=7÷ = :30== %
3÷5= = :15== %
0.4= :4=4÷ = %