What is the probability of a certain event?

• A probability of an event reflects the chance or likelihood that a particular event will occur. 
• The probability of an event can be calculated as:$\frac{\mathrm{Number} \mathrm{of} \mathrm{favourable} \mathrm{outcomes} \mathrm{of} \mathrm{an} \mathrm{event}}{\mathrm{Total} \mathrm{possible} \mathrm{outcomes} \mathrm{of} \mathrm{an} \mathrm{event}}$
• Probability can range from 0 to 1.
• A certain event is one that will definitely occur. That means all the possible outcomes are favourable. Hence the probability of the event will be maximum which is 1.
• For example, an event of receiving a number less than seven when a dice is rolled is a certain event with probability 1.

Therefore, we can say that the probability of a certain event is 1.