The Probability of Sure Event is:

The probability of a sure event is always 1 or 100%.

In probability theory, the probability of an event is a measure of the likelihood that the event will occur. The probability of any event ranges from 0 to 1, where 0 indicates impossibility and 1 indicates certainty. A sure event is one that is guaranteed to happen, and therefore, its probability is 1.

For a sure event, every outcome in the sample space is a favorable outcome, as the event is certain to occur. Therefore, the probability of a sure event is calculated as:

P (Sure Event) = ​Number of Favourable Outcomes/Total Number of Possible Outcomes

Since the number of favorable outcomes is equal to the total number of possible outcomes for a sure event, the probability simplifies to:

P (Sure Event) = Total Number of Possible Outcomes/Total Number of Possible Outcomes ​= 1

This demonstrates that the probability of a sure event is indeed 1, indicating complete certainty of its occurrence.

Related Article:

• What is the Probability of a Possible Event?

Practice Problems - The Probability of Sure Event

Q1. Consider an experiment where a die is rolled. What is the probability of rolling a number between 1 and 6?

Q2. In a deck of 52 cards, what is the probability of drawing any card?

Q3. A bag contains 5 red balls. What is the probability of drawing a red ball?

Q4. If a coin is tossed, what is the probability that the result will be either heads or tails?

Q5. A jar contains 7 marbles of different colors. What is the probability of picking any one marble?

Q6. What is the probability of choosing a student from a class of 30?

Q7. What is the probability of selecting a day of the week?

Q8. In a lottery with 1000 tickets, what is the probability of winning if you have all 1000 tickets?

Q9. A wheel with 12 equal segments is spun. What is the probability of landing on any segment?

Q10. A box contains 10 identical pens. What is the probability of picking any pen?