Complete the questions on page 206 (11a, 11b, 11c, 12a, 12b, 13a, 13b) for practice in recognizing mutually exclusive and non-mutually exclusive events and representing them in Venn diagrams.

Click here to verify your answers .

 

Now that you can identify mutually exclusive and non-mutually exclusive events and represent them in Venn diagrams, you can begin to solve probability problems.

Mutually exclusive and non-mutually exclusive events are known as or probabilities. This can be seen in examples at the beginning of the Training Camp . The events in each example are linked with the word or . This is reflected in the formulas for calculating probability of mutually exclusive and non-mutually exclusive events. The remainder of this lesson explores how to use these formulas to solve probability problems. Begin with mutually exclusive events.

For any two mutually exclusive events, the probability that event A or event B will occur is given by the formula:

In Unit 1, you learned that the union of two sets A and B is denoted . This notation can be used to rewrite the above formula.

Examples 1 and 2 illustrate how to use this formula.

 

 

A card is drawn from a standard deck of 52 cards. What is the probability that the card drawn is a black card or a heart?

Because no card is black and a heart at the same time, these events are mutually exclusive. Therefore, use the formula for probability of mutually exclusive events.

A standard deck of cards is half black and half red, so the outcome of drawing a black card has a probability of . Because a standard deck has 4 suits (hearts, diamonds, clubs, and spades), the outcome of drawing a heart is .

The probability of drawing a black card or a heart is 0.75 or 75%.