甲乙两个齿轮齿数比是3:5,它们互相咬合.当甲齿轮转50圈时,乙齿轮转 圈.
20%= ÷40= <填小数>=× = 成.
== ÷ = (最简分数)
3﹕ ==0•375=6÷ = %
=0.4=12: =6: = %.
÷8=3: =25%= 填小数.