Hi
The basic rule of 3 is represented by this equation a/b=a2/b2
For example if 2 apples cost 3dollars, how many apples can I get with 5$ ? —>> 2/3=x/5

In case of the compound rule of three, this should be the equation a/b/c=a2/b2/c2
Is this always right ? Or is it right depending on inverse/direct proportionality between a,b and c?