大、小两瓶饮料共1.2升,大瓶中的饮料被喝掉0.4升,这时大瓶与小瓶内的饮料之比是3:1,大小两瓶饮料原来的比是 .
= : =15÷ = %
= :20=4.5÷ = %=0.5 .
15÷ ==9: = %=0.75.
9: ==36÷ = :45= (填小数)
%= ÷8==0.75= (填成数).