A direct correlation between two variables is y = kx where k is a constant. In inverse relationship is y=k/x.
Answer:

The balance is $256
Step-by-step explanation:
Given


Required
Determine the balance after 20 visits
Represent the balance with b
Represent the visitation with v
The relationship between the given parameters is:

This gives:


Make b the subject

To get the actual balance after 20 visitation;
Substitute 20 for v



Hence:
<em>The balance is $256</em>
I think for mo it’s 18 and for zo it’s 10