To find the number of visits per month at which the two plans are equal, we can set up an equation based on the cost structure of each plan.
Let \( x \) be the number of visits per month.
For the first plan, the cost is: \[ \text{Cost}_1 = 8x \]
For the second plan, the cost is: \[ \text{Cost}_2 = 40 + 2x \]
To find the number of visits where the costs are equal, we set the two costs equal to each other:
\[ 8x = 40 + 2x \]
This equation can be solved for \( x \) to find the number of visits at which both plans cost the same.