2003 AMC 10A Problem 21
Problem 21 of 25HarderCombinatorics
Pat is to select six cookies from a tray containing only chocolate chip, oatmeal, and peanut butter cookies. There are at least six of each of these three kinds of cookies on the tray. How many different assortments of six cookies can be selected?
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Solution
An assortment is determined by how many of each type are chosen, so we count nonnegative integer solutions to
By stars and bars, placing dividers among slots gives assortments.
Thus, the correct answer is D.
Tagged: stars and bars