Question

what is the probability of an event that is certain?

Explanation:

Step1: Recall probability definition

Probability of an event \(E\) is \(P(E)=\frac{\text{Number of favorable outcomes}}{\text{Total number of outcomes}}\).

Step2: For a certain event

A certain event has all outcomes as favorable. Let total number of outcomes be \(n\). Number of favorable outcomes is also \(n\). So \(P(E)=\frac{n}{n} = 1\).

Answer:

\(1\)