Miltong, Thanks. I see the logic. 100% minus the probability that ALL 3 fail = At least 1 succeeds 2.7% all fail (30%*30%*30%)
Then even if the probability for fail is 70% for each, the probability that all 3 fail is only 34% (70%*70%*70%). That still leaves a 66% probability that at least one will succeed... looks like a VC fund investment model.