配制一种盐水,盐的重量是水的,盐和盐水重量的比是 : .
:16==24÷ = %
9÷ = :48=0.75= %= 折数.
:12=6÷ = 填小数= 折=75%.
=0.4==12÷ = %= :25.
= (小数)= (百分数)=12: = 折.