Arturo is selling ads for his school paper, the gab gazette. burger binge, cobbies' fish & chips, and doolittle donuts all want to buy ads, but arturo has only one page left to fill. the sizes of his ads are 1/2, 1/4,1/8, 1/16 of a page. before arturo sells the ads to the restaurants, he has t figure out all of the different combinations of his ads that would fill one page. how many combinations are there?