用一根绳测井深,将绳三折去量,井口外余三米;四折去量,余一米.井深几米?绳长几米?
问题描述：
用一根绳测井深,将绳三折去量,井口外余三米;四折去量,余一米.井深几米?绳长几米?
答
设井深x米.
则3(x+3)=4(x+1)
=>3x+9=4x+4
x=5
3(x+3)=3*(5+3)=3*8=24米——绳长