Definition Of Certain Event

An event that is certain to occur is called Certain Event.

More About Certain Event

The probability of a certain event is always 1.

Example of Certain Event

The Christmas will be celebrated on the 25th of December this year. This is a certain event.
It is 2:00 p.m. now and will be 4:00 p.m. after two hours. This is a certain event.

Video Examples: icoachmath works

Solved Example on Certain Event

Ques: A teacher chooses a student at random from a class of 30 boys. What is the probability that the student chosen is a boy?

Choices:

A.1/30
B.1/29
C. 0
D. 1
Correct Answer: D

Solution:

Step 1: Number of students in a class is 30. So, the number of possible outcomes is 30.
Step 2: Since all the students in the class are boys, the number of favorable outcomes is 30.
Step 3: Probability (event) =  [Formula.]
Step 4: P (boy) =30/30 = 1 [Substitute the values.]
Step 5: The probability that the student chosen is a boy is 1.

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