>>9547612It's 1 - {the probability that no one gets shocked}.
So there's a 50% chance that the first person doesn't get shocked. There's also a 50% chance that the second person doesn't get shocked, so there's a (50%)*(50%) = 25% chance that neither of them gets shocked. There's a 50% chance that the third person doesn't get shocked, so there's a (25%)*(50%) = 12.5% chance that none of the first 3 people get shocked. Doing the same thing for the next 2 people gets us a 3.125% chance that no one gets shocked.
We know that either (no one gets shocked) or (at least one person gets shocked). It's impossible for both to be true and it's impossible for neither to be true. Therefore, if we add the probabilities of those together we must get 1. From this we can infer that 1 - (probability that no one gets shocked) = (probability that at least one person gets shocked) = 100% - 3.125% = 96.875%.
You should pick up a book on probability and study discrete probability distributions, at least a bit. This problem is a specific case of the binomial distribution
https://en.wikipedia.org/wiki/Binomial_distribution.