3/5:4/15
=3/5*15/4
=9/4解比例：五分之一：x=八十分之三：十分之三1/5:x=3/80:3/101/5*3/10=3x/803/50=3x/80150x=240x=8/5如有帮助，请采纳!3x/80是八十分之3x吗？是