Question 1062095

Sorry to submit problem again, but has been over an hour.  Problem:  Went to Staples to have cards printed. They charge a base fee of $15 and 12 cent each card printed. Prints were ordered and paid $45 before taxes. How many cards were ordered to be printed.  Thanks for your time and help
<pre>With x being number of cards printed, we get: f(x) = .12x + 15
45 = .12x + 15 ------- Replacing f(x) with 45 
45 - 15 = .12x
30 = .12x
Number of cards printed = {{{highlight_green(matrix(1,3, 30/.12, or, 250))}}}