To clarify the relationship between the variables:
- The independent variable, \( x \), represents the number of coffee cups purchased.
- The dependent variable is the total monthly cost, because the total cost depends on the number of cups of coffee purchased.
The function relating these variables can be expressed as:
\[ A(x) = 20 + 2.5x \]
where \( 20 \) is the monthly fee for the program and \( 2.5x \) is the cost of the coffee cups purchased at a price of \( 2.5 \) per cup.
Now, calculating for \( A(7) \) (when \( x = 7 \)):
\[ A(7) = 20 + 2.5 \times 7 \] \[ A(7) = 20 + 17.5 \] \[ A(7) = 37.5 \]
So, \( A(7) = 37.5 \), meaning $37.5 will be paid for 7 cups of coffee.