[NoSoup4U]

As always, you are the man. We were missing the idea of subtracting your risk of ruin at the upper end, which was resulting in numbers that we knew defied reason. Your method results in numbers that "feel" more accurate.

If you'll indulge me, I think this results in:

.5/1 -> 1/2 .787
1/2 -> 2/4 .787
2/4 -> 3/6 .884 (only need 30 BBs to advance)
3/6 -> 5/10 .849
5/10 -> 10/20 .787
10/20 -> 15/30 .884
Total = 32.3 chance of success. This seems much more like I thought it would be. Maybe even a bit higher than I expected.

However, when I try to adjust for 2 bb/100, something seems wrong. I'm doing:

exp((-2 * 2 * 20) / (18^2)) = 0.781 - exp((-2 * 2 * 40) / (18^2)) = 0.610
which says I have only a 17.1% chance of busting if my earn-rate is lower.

Can this be correct or have I missed something fundamental?

Thanks for your help.