# RD Sharma Solutions for Class 9 Maths Chapter 25: Probability

This chapter discusses formulas, questions and answers of "Probability". Probability has taken an important place in the mathematics book due to its heavy usage in real life. However, the probability is nothing but a chance of an event to occur. The best example of probability is "Tossing a coin". It has two sides, Head and Tail. Between the two sides of the coin, only one side can get a result of the toss, either head or tail. So, the probability of getting head or tail becomes 12. But what we can see from here is that many events cannot be predicted by certainty. So what we have to remember is the value of probability always lies between 0 to 1.

The main procedure of determining the value of probability is by differentiating the possibility of the event to occur and not to occur and then dividing the number by a total number of events. Several terms which are important to know in this chapter are:

• The trial is the occurrence of an experiment. A trial can be done once or infinitely repeated to get the possible outcomes.
• An experiment is several trials that are taking place to measure the event's chance.
• An Event is something that is occurring or may occur in the future.
• A Sample Space is the set of all possible outcomes of trials.
• The outcome of an experiment is called Result

Probability = Favourable Event/Total number of Events