# 11.4.1. Calculating Probability

5 Russian, 6 Italian, and 29 French tourists went on a package tour. If one of them is randomly chosen to conduct a survey on the tour, determine the probability of selecting a French or Italian tourist.

• A
0.875
• B
0.125
• C0.15
• D
0.725

### Example

5 Russian, 6 Italian, and 29 French tourists went on a package tour. If one of them is randomly chosen to conduct a survey on the tour, determine the probability of selecting a French or Italian tourist.

### Solution

The probability of event occurring is equal to the number of favorable outcomes divided by the total number of possible outcomes in the sample space, . In this case, event is selecting a French tourist. Find the probability of event as follows:

The probability of event occurring is equal to the number of favorable outcomes divided by the total number of possible outcomes in the sample space, . In this case, event is selecting an Italian tourist. Find the probability of event as follows:

The notation refers to the probability of either event or event occurring. Since and are two mutually exclusive events, then . Now use this fact to determine the probability of .

Thus, the probability of selecting a French or Italian tourist is 0.875.

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