Hello,
now, i really broke my brain on that one because I could not find any answer matching the given ones.
I even asked two more people, each of which getting a different impression on how the experiment was supposed to be understood.
So i’d like to propose a bit of a ‘re-wording’ (given that I now understood it correctly 
):
“You roll a dice. If it shows a value less than 4 (excluding 4), you roll two dice and sum the result of the second double-dice-roll. Otherwise, if the first roll shows a number greater than 3, you roll a single dice and obtain your result from the number this second single-dice-roll shows.
What is the probability of getting a 6 as final result after the second roll”
Did I get this one right, or is there maybe still something wrong with my approach?
Those were the two other ways it was understood:
I)
- Sum the first single-dice-roll with the second single-dice-roll, if first roll gives <4
- Sum second double-dice-roll
II) - Take the first roll, given you obtain a 6, done
- if value >4, roll two-dice and sum up
- If the result of the DOUBLE-DICE-roll is <4, do another single-dice-roll and obtain value from second single-dice-roll
(That way it’s three layers)
Hope that can be useful.
regards,
Christian