You are thinking of advertising Microsoft products on a sports telecast. As you buy more ads, the price of each ad decreases as shown in the following table:
|
Number of ads
|
Price per ad
|
|
1-5
|
$ 12,000
|
|
6-10
|
$11,000
|
|
11-20
|
$10,000
|
|
21 and higher
|
$ 9000
|
For example, if you buy 8 ads, you pay $11,000 per ad, but if you buy 14 ads, you pay $10,000 per ad. Write a formula that yields the total cost of purchasing any number of ads.