The document contains a series of mathematical equations involving the variable ρ. The equations are divided into three sections labeled low group, middle group, and high group. Each section contains multiple equations that can be solved to find the value of ρ. The overall document appears to be providing examples of solving for an unknown variable ρ based on given equations.

1. Low group
9 x  = 90
45
=5
x 13 = 130
 4 = 32
5 x  = 25
110
 = 11
x 9 = 27

3 = 24
7 x  = 35
125
 = 12.5
 x 1.5 = 15

10 = 14.9

2. Middle groups
1.9 x  = 7.6
453
 = 75.5
 x 13 = 80.6

5.2 x  = 15.6
12
 = 2.4
 x 19 = 85.5
4 = 35
 4 = 3.8
3 x  = 4.2
5 x  = 34
25.6
 = 12.8
56.4
 = 9.4
7.6 x  = 68.4
125
 = 12.5
 x 1.6 = 14.4

10 = 14.9
9 x  = 41.4
125.4
 = 41.8

3. High groups
11.4 x  = 68.4
53.2 x  = 638.4
7.6 x  = 121.6
15.2  = 3.8
12.4  = 3.1
162.8  = 81.4
 x 13 = 214.5
 x 19 = 47.5
 x 1.6 = 91.2
 4 = 12.1
 2.5 = 8.4

16 x  = 265.6
23 x  = 326.6
25.6
 = 12.8
56.4
 = 9.4
100 = 14.9
6.5 x  = 84.5
125.4
 = 41.8