1.设绳长为x(由两次测量的井深=井深著手)
,(x-6)/3=(x+4)/4,x=36
井深=(x-6)/3=10
2.设绳长为x
x/4 +1 =x/3 -2,3x+12=4x-24,x=36
井深=36/4+1=10