Roll a die repeatedly. Say that you stop when the sum goes above 63. What is the probability that the second to last value was X. Make a market on this probability. Ie what is your 90 percent confidence interval.

Step-by-step explanation: Since we are considering a die, knowing fully well that it has 6 faces from 1-6

X=63, 6 possible last roll as 1,2,3,4,5,6;

X=62, 5 possible last roll as 2,3,4,5,6;

X=61, 4 possible last roll as 3,4,5,6;

X=60, 3 possible last roll as 4,5,6;

X=59, 2 possible last roll as 5,6;

X=58, 1 possible last roll as 6.