Answer:
and

Explanation:
Represent white paint with w and black with b
Given
When w = 3; b = 1
Required
Determine the two equations
To get a gray paint, the w and b are needed in the following proportion:
-----(1)
Solve for b

Reorder

---- This is an equation
To get another equation,
Recall that

Solve for w


Make w the subject

Hence, the equations that show the relationship between w and b are:
and
