Answer: the total cost for an order of 20 copies is $13.9
Step-by-step explanation:
Let x represent the number of copies ordered.
The printing service charges a set-up fee of $12.50 for each order and 7 cents more for each copy.
The equation representing the total cost, C (in dollars), for an order of x copies is expressed as
C = 0.07x + 12.50
Therefore, the total cost for an order of 20 copies would be
C = 0.07 × 20 + 12.5
C = 1.4 + 12.5
C = 13.9 dollars