 Hello and welcome to the session. Let us discuss the following question. It says a coin is tossed twice. What is the probability that at least one tail occurs? Before moving on to the solution, let us first understand the formula for the probability of any event E. The probability of any event E is given by number of outcomes favourable to E upon the total number of outcomes. This knowledge will work as key idea. Let us now proceed on with the solution. As we know that whenever we do some experiment, it has some outcomes. So here we are tossing a coin. And we know that whenever we toss a coin, there are two possibilities. Either we get a head or we get a tail. So here we first need to make a sample space of the experiment tossing a coin twice. And since the coin is tossed twice, the number of outcomes will be 4. So here we see that what are these outcomes? We are tossing a coin twice. So it may possible that in both the toss we get head. Then it is possible in the first toss we get a head. And in the second toss we get a tail. And it is possible that in the first toss we get a tail. And in the second toss we get a head. And one more possibility is that we get tail in both the toss. So the total number of outcomes, so the total number of outcomes are 4. And in the event when we get at least one tail, which are the favorable outcomes to E, that is when we get at least one tail, that is we can get one tail or we can get more than one tail. So the favorable outcomes to E are head-tail, tail-head and tail-tail. So these are three outcomes favorable to E. Probability of getting at least one tail is number of outcomes favorable to E, that is 3 upon the total number of outcomes, that is 4. Hence the probability is 3 by 4. This completes the question and the session. Bye for now. Take care. Have a good day.