一条钢筋,用去了12份之5,比余下的短6米.这条钢筋长几米?剩下多少米?

问题描述:

一条钢筋,用去了12份之5,比余下的短6米.这条钢筋长几米?剩下多少米?

设这条钢筋有X米,那么
(7/12)X-(5/12)X=6
(2/12)X=6
X=36
所以这条钢筋长36米,剩下(7/12)*36=21米.