HSC Maths Standard 2 | "At Least One" Probability Rule

[00:00:00]hi guys so in this video I'm going to be talking about how to solve for the probability of at least one event occurring so at least one means of the event has to occur one or more times so the formula for solving for the probability of at least one is equal to one minus the probability of none occurring so for example let's say we have two die and each has numbers from 1 to 6 and we want to find the probability of rolling at least 1 3 so you set out your equations so that you see the probability of at least 1 3 is equal to 1 minus the probability of rolling no 3s so that's equal to 1 minus 5 over 6 times 5 over 6 because when you roll the first die you'd have 5 numbers that you can get because there's no 3s and then the same happens for the second die and then you simplify this so it's equal to 1 minus 25 over 36 and then this should equal 11 over 36 so that's how you find the probability of at least one thanks guys you [Music]