If something has a 10% success rate and you attempted that thing 10 times, what''s the likelihood that you''d succeed? On first glance, some might answer 100% or maybe even very close to 100%, but that''s just not how probability works. In this case, it''s easier to calculate the probability of failing all 10 attempts. There''s a 90% chance of failing one attempt. There''s a 81% (0.9 x 0.9) chance of falling two attempts. Continue this and you''ll end up with a 34.87% (0.9^10) chance of failing 10 times.


    Thus the success rate would be 65.13% (1 - 0.9^10).


    Even at 20 attempts, the success probability would still be below 90% (at around 87.84%).