Probability Formula Class 9

Probability of an event can be calculated by applying the probability formula. It is determined by simply dividing the favorable number of outcomes by the total number of possible outcomes. Students can learn to determine the probabilities of various events by memorizing the probability formula class 9. This article provides a list of important probability formulas along with some useful tips to help students comprehend the idea of probability.

List of Probability Formula Class 9

Students can refer to the important concepts and formulas explained below in the list of Probability Formula Class 9:

• Event: An event for an experiment is the collection of some outcomes of the experiment.
• The empirical (or experimental) probability P(E) of an event E is given by

P(E) = Number of trials in which E has happened/Total number of trials

• The Probability of an event lies between 0 and 1 (0 and 1 inclusive)

Applications of Probability Formula Class 9

Probability formulas are applied extensively in various sciences like medical sciences, physical sciences, weather forecasting, commerce, etc. Here are a few examples of

applications of probability formulas class 9:

• Probability formulas are used by meteorologists in determining the probability of earthquakes in an area. This probability is calculated based on the occurrence of earthquakes in that area so far.

• Based on the number of times a team has won a tournament in the past the probability of the team winning the next tournament can be calculated by applying Probability formulas class 9.

Probability Formula Class 9 Examples

Example 1: Two identical coins are tossed 100 times and we get the frequency distribution as -

Two Heads: 30 times

Two Tails: 40 times

One Head: 30 times

Find the probability of each of the above three possible outcomes?

Solution :

Probability of Getting two heads = E1 = 30/100 = 0.3

Probability of Getting two tails = E2 = 40/100 = 0.4

Probability of Getting one head = E3 = 30/100 = 0.3

Also, we can see sum of E1 + E2 + E3 = 1

Example 2: In a survey done for 200 students, 90 students like to play football and 110 students like to play cricket. What is the probability of selecting a student who likes to play cricket and football?

Solution: Probability = Number of students who like cricket/Total students

= 110 /200

= 11/20 = 0.55

Tips to Memorize Probability Formula Class 9

Students can learn the probability formula class 9 by following the tips below:

• Writing down formulas is one of the most effective ways to retain them. Students will gain a better comprehension of the concepts and formulas if they practice this on a daily basis.

• Students must go over all of the solved examples in their textbook and attempt to solve them on their own after they understand the logic behind the formulas. This will help them get familiarized with range of formula applications. They should then practice the exercise questions to have enough problem-solving experience.

• Students can download formula images to use them as wallpaper on their computers and mobile devices. This will provide them with a quick revision every time they use these devices.

Students can download the printable Maths Formulas Class 9 sheet from below.