# 11.4.1. Calculating Probability

In one of the shows at the pyramids, one of the tourists is chosen randomly to win a prize, and the table below represents the number of tourists of different nationalities. Determine the probability that the chosen tourist is Russian or Greek.

AttendenceRussiansGreeksAmericansTotal
Men50101575
Women608035175
Total1109050250
• A0.8
• B0.64
• C0.56
• D0.44

### Example

In one of the shows at the pyramids, one of the tourists is chosen randomly to win a prize, and the table below represents the number of tourists of different nationalities. Determine the probability that the chosen tourist is Russian or Greek.

AttendenceRussiansGreeksAmericansTotal
Men50101575
Women608035175
Total1109050250

### 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 Russian 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 a Greek tourist. Now find the probability of event .

The notation refers to the probability of either event or event occurring. Also, the events and must be mutually exclusive, because the sum of the numbers of Russian tourists, Greek tourists, and American tourists equals the total number of tourists at the show. Since and are two mutually exclusive events, then Next, use this fact to determine the probability of

Thus, the probability of selecting a Russian tourist or a Greek tourist is 0.8.

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