设树苗有x棵,公路长为3×(x-5)米.
由题意,得:1.5×(115+x)=3×(x-5)
1.5×115+1.5x =3x-15
1.5x-3x =-15-172.5
-1.5x =-187.5
x = 125
∴3×(x-5)=3×(125-5)=360米
设树苗有x棵,公路长为3×(x-5)米.
由题意,得:1.5×(115+x)=3×(x-5)
1.5×115+1.5x =3x-15
1.5x-3x =-15-172.5
-1.5x =-187.5
x = 125
∴3×(x-5)=3×(125-5)=360米