Multiplication of Probabilities - SS2 Mathematics Lesson Note

The probability of the simultaneous or successive occurrences of two or more independent events is equal to the product of their separate probabilities.

$$P(AandB)=P(A\cap B)=P(A)P(B)$$

Example: What is the probability of 2 heads from the toss of a coin twice?

Solution

$$P(2heads)=P(headfrom1sttoss)\times P(headfrom2ndtoss)$$

$$P(2heads)=\frac{1}{2}\times \frac{1}{2}=\frac{1}{4}$$