1. The stamp ratio of Xiao Ming and Xiao Li is 1:4. Xiao Ming has 72 fewer stamps than Xiao Li. How many stamps does Xiao Li have 2. Suppose that the ratio of salt to water in brine is 1:9, then salt accounts for ()% (write the answer directly) 3. The scale of a part drawing is 7:1. If the length of the part measured on the drawing is 49mm, how many mm is the actual length 4. The survey team measured the height of the TV Tower and got the shadow length of 45 meters. At the same time, the shadow length of a 10 meter high column nearby was 2 meters. What's the height of the TV Tower? (to give the formula)

1. The stamp ratio of Xiao Ming and Xiao Li is 1:4. Xiao Ming has 72 fewer stamps than Xiao Li. How many stamps does Xiao Li have 2. Suppose that the ratio of salt to water in brine is 1:9, then salt accounts for ()% (write the answer directly) 3. The scale of a part drawing is 7:1. If the length of the part measured on the drawing is 49mm, how many mm is the actual length 4. The survey team measured the height of the TV Tower and got the shadow length of 45 meters. At the same time, the shadow length of a 10 meter high column nearby was 2 meters. What's the height of the TV Tower? (to give the formula)

1. Set Xiaoming's stamp as X
X+72=4X
The solution is x = 24
Xiao Li's number of sheets is 24 + 72 = 96
2.80%
3.49/7=7mm
I don't know if you are a junior high school student. Have you ever learned something similar
Let the height of TV tower be XM
X/45=10/2
The solution is x = 225m

Xiao Ming collects 40 more stamps than Xiao Li. Xiao Li collects 0.6 of Xiao Ming's. how many stamps does Xiao Ming collect

Steps: 1. Let Xiao Ming have X and Xiao Li have y
2. Column relation x-40 = y (1)
x*0.6=y （2）
3. Solving the equations will bring (2) into (1)
x-40=0.6*x
4. Results x = 100, y = 60
The answer is very detailed~

Xiaoming, Xiaoli and Xiaolu all like to collect stamps. Xiaoming: each of us has 45 stamps on average. Xiaolu said: the number of stamps of Xiaoming and Xiaoli is 5:7:3. Xiaoli said: how many stamps do we each have?

Let Xiaoming have 7K, Xiaoli 3K and Xiaolu 5K
7k+3k+5k=45×3
15k=135
k=9
Xiao Mingyou: 7 × 9 = 63 (sheet)
Xiaoliyou: 3 × 9 = 27 (sheet)
Xiaoluyou: 5 × 9 = 15 (sheet)
I'm tired of writing