Answer:
Class A : 

Class B : 

Explanation:
Class A : 
Let the amount of Salt in the solution be represented by y as, it is supposed to be the independent variable. 
Similarly let the amount of Water in the solution be x 
As we are given that for Class A , The ratio of salt content to water content is 3 to 5 
Hence 

Multiplying both sides by x we get

Class B : 
Let the amount of Salt in the solution be represented by y as, it is supposed to be the independent variable. 
Similarly let the amount of Water in the solution be x 
As we are given that for Class A , The ratio of salt content to water content is 2 to 4 
Hence 

multiplying both sides by x we get
