Solution to this problem: https://twitter.com/nntaleb/status/907204053079400448
The dice will be rolled no more than 3 times. Smallest even number is 2 and 2x3=6, which is the desired sum.
Now, the problem statement says that we roll the dice only until we get the sum of 6 or more. Yet, nothing would change, if we rolled the dice exactly for 3 times, but ignored all rolls after we reach 6.
Now, naive solution would be to generate all triplets from numbers 2, 4, 6 and determine how many of them achieved sum >=6 after first, second, or third item. It's the very same thing Nassim Nicholas Taleb has done here: https://twitter.com/nntaleb/status/907211482743668737