Question

Can any body help my son with this is very important please some body help him in tanks very much I hope some body help me

Answer 1

The top box on the page explains the idea completely.
You need to read the top box several times, and understand it.
A ratio is a comparison of two quantities by division.

1). Days in May: 31
     Days in a year:  365
     Their ratio:    31/365 .

2).  Sides of a triangle:  3
       Sides of a square:  4
       Their ratio:        3/4 .

The middle box explains how two ratios can be equal,
and it gives you a very detailed example.  You should
read the middle box and understand it.
Ratios are fractions.  They can be equal in just the same
way that any two fractions can be equal. 
And you can simplify ratios in exactly the same way that
you simplify fractions ... divide top and bottom both by
the same number.

3).  8/12         Cook up three equal ratios.
       1.  divide top and bottom by 2 . . . . . 4/6
       2.  divide top and bottom by 4 . . . . . 2/3
       3.  multiply top and bottom by 9 . . . . 72/108
       These are just some that I chose.
       There are millions of others. 

4).  20/25      Cook up three equal ratios.
       1.  divide top and bottom by 5 . . . . . 4/5
       2.  multiply top and bottom by 4 . . . . 80/100
       3.  multiply top and bottom by 3 . . . . 60/75
       These are just some that I chose.
       There are millions of others. 

5).  5/6         Cook up three equal ratios.
       1.  multiply top and bottom by 2 . . . . 10/12
       2.  multiply top and bottom by 3 . . . .
       3.  multiply top and bottom by 9 . . . . 45/54
       These are just some that I chose.
       There are millions of others. 

6).   10/14         Cook up three equal ratios.
       1.  divide top and bottom by 2 . . . . 5/7
       2.  multiply top and bottom by 2 . . . .
       3.  multiply top and bottom by (you choose) . . . .