A "Be Prepared" test prep book costs $18.95; "Next Best" costs $21.95. A site called apzone.com offers a special deal: both for $37.95. If you buy three or more copies (in any mix of these two titles), they are $15.98 each. If you buy 12 or more copies, you pay only $14.00 for each. Write a method that calculates the total for an order of bp copies of "Be Prepared" and nb copies of "Next Best," taking the above specials into account.