一项工程 甲队单独完成需要20天,乙要30天,合作完成几分之几

问题描述:

一项工程 甲队单独完成需要20天,乙要30天,合作完成几分之几

........................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................1/20+1/30=5/60=1/12

1/20+1/30=5/60=1/12