1、

Set the original plan to lay x meters every day.

(300- 120)/ 1.2x+ 120/x = 27

That is 150+ 120=27x.

The solution is x= 10.

2、

(300 \ 10-27)x 4000 = 12000

A: It was originally planned to lay 10 meter a day, but now it is less than the original plan 12000 yuan.