VoteAnswers? - Results (6 votes)Paying $2 is always better33.33% (2 votes)2Paying $3 is always better16.67% (1 vote)1They're both statistically the same50% (3 votes)3
You require 12 special event items to complete an objective
You have two opportunities:
You can pay $2(gold/gems/doubloons/whatever) for a 33% chance at one
You can pay $3 for a 50% chance at one.
The goal is to get all 12 for the lowest cost. The items are interchangable so you don't need to get a specific item, just a total of 12.
The naive impression is that both situations are equal, it should take an average of $72 in either case, but what's the real answer?