An advertisement has a picture of a vacuum cleaner. From top to bottom, the text of the ad is as follows.

Question

12 amp Powervac Plus
$89.99
Microfiltration
On-board tools
1 year Product Replacement Policy, $7.99
(a)
What is the percent markup based on selling price?
35
%
(b)
If the retailer pays $1.70 to the insurance company for each product replacement policy sold, what is the percent markup based on selling price of the vacuum cleaner and policy combination?
%
(c)
If 6,000 vacuum cleaners are sold in a season and 40% are sold with the insurance policy, how many additional "markup dollars," the gross margin, were made by offering the policy?
$