The first 1 represents the investment amount before 1 month, and then multiplied by the percentage after two reductions, which is equal to the percentage after two months.
2. If the width of paved road is x and the total area of this land is 6× 10=60, then the area of road and grassland should be equal, which is 30.
Imagine that the road area should be: x×6×2+x×( 10-2x)=30.
It can also be listed as an equation with grassland area of 30, that is, grassland area is: (10-2x)×(6-2x)=30.
(For homework or exams, the 30 on the right side of the equation should be changed to 6× 10× 1/2. Write 30 here for the convenience of understanding. The one on the first floor of ps is wrong. There are roads on both sides, and he only subtracts an x)
The above is the train of thought, do it yourself ~ ~ If you are satisfied, please choose my answer ~ I will try my best to answer the question.