The problem of "practically solving the equation of one variable and one degree" in grade one of junior high school A shopping mall sells two goods at 99 yuan. One loses 10% and the other makes 10% profit. Is it a loss or a profit for the total price of two goods

The problem of "practically solving the equation of one variable and one degree" in grade one of junior high school A shopping mall sells two goods at 99 yuan. One loses 10% and the other makes 10% profit. Is it a loss or a profit for the total price of two goods

Suppose that the original price of a profitable commodity is X Yuan and that of a loss commodity is y yuan
（1+10％）X=99
X = 90 yuan
The profit of a commodity is 99-90 = 9 yuan
(1-10%)Y=99
Y=110
The loss of a commodity is 110-99 = 11 yuan
11 is greater than 9
Therefore, the total price of two commodities sold in the mall is a loss

In the first year of junior high school, the problem is solved by the equation of one variable and one degree
When Xiao Ming was working by hand, he cut a 3 cm wide strip from a square piece of iron, and then cut a 4 cm wide strip from the remaining rectangular piece of iron along the short side. If the two strips are equal in area, what is the original side length of the square piece of iron?
1. Plant a batch of poplar seedlings on both sides of a road. If one tree is planted every 3 meters, there will be 3 seedlings left; if one tree is planted every 2.5 meters, there will be 77 seedlings left. Find the length of the road and the number of saplings.
2. A cylindrical iron bucket with an inner diameter of 20 cm and a height of 55 cm contains water 40 cm deep.
(1) First, put the square iron block with the side length of 8 cm into the bucket slowly. How many centimeters has the water level in the bucket risen?
(2) Take out the iron block in the bucket and put a solid cylindrical object with a bottom diameter of 8cm and a height of 40cm into the bucket. Will the water in the bucket overflow? Why. (3.14 for PAI)

If there are x trees, there are 3 (x-3) roads
3（x-3)=2.5(x+77)
3x-9=2.5x+1925
0.5x=1934
x=3864
3 (x-3) = 3 × (3864-3) = 11583 (m)
Answer: