Baskin Robbins serves "31 Flavors" of ice cream. How many different two-scoop ice cream cones are possible if two different flavors are used on each cone and the order of the scoops doesn't matter?* (* Means chocolate on top and vanilla on the bottom is the same as chocolate on the bottom and vanilla on top.)© BrainMass Inc. brainmass.com September 26, 2022, 9:01 pm ad1c9bdddf
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This is a "pick k out of n" problem.
with no order, it is:
Where n! is n factorial:
n! = ...
The solution shows how to reach the answer first by simple plug-n-chug and then explains how to do it using simple principles.