 Hi and welcome to the session. Let us discuss the following question. Question says complete the following statements. Second part is the probability of an event that cannot happen is dash. Such an event is called dash. Let us now start with the solution. First of all let us understand that the probability of an event which is impossible to occur is zero and such an event is called impossible event. Now from this discussion we get probability of an event that cannot happen is zero. Such an event is called impossible event. We know probability of an event E is equal to number of outcomes favorable to event E upon total number of possible outcomes. Now we know an event which cannot happen has the outcome equal to zero so we get number of outcomes favorable to impossible event is equal to zero. Now substituting this value zero in this expression we get probability of an event E is equal to zero upon total possible outcomes that is further equal to zero only so we get the probability of an event that cannot happen is zero and such an event is called impossible event. This is our required answer. This completes the session. Let me understood the solution. Take care and have a nice day.