Probability is a numerical measure of the likelihood of occurrence of an event. The value of probability lies between 0 and 1.

If all outcomes of an experiment are equally likely, then the probability is given by, Probability of an event =

Video Examples: Introduction to Probability

Example of Probability

The probability to pick a blue marble from a basket containing 10 blue marbles is 1.
Suppose you toss a fair coin. Then the probability of tossing a head or tail is 1/2

Solved Example on Probability

Ques: A basket contains 30 apples, 20 pears and 10 peaches. What is the probability that the first piece of fruit taken from the basket will be a peach?

Choices:

A. 1/3
B.1/2
C.1/6
D.1/5
Correct Answer: C

Solution:

Step 1: Total number of fruits in the basket = 30 + 20 + 10 = 60.
Step 2: Number of peaches in the basket = 10.
Step 3: The probability of taking a peach from the basket 10/60 =1/6 . [From the definition.]