Elizabeth lives in San Francisco and works in Mountain View. In the morning, she has 3 transportation options (take a bus, a cab, or a train) to work, and in the evening she has the same 3 choices for her trip home.If Elizabeth randomly chooses her ride in the morning and in the evening, what is the probability that she'll use a cab exactly one time?
Q. Elizabeth lives in San Francisco and works in Mountain View. In the morning, she has 3 transportation options (take a bus, a cab, or a train) to work, and in the evening she has the same 3 choices for her trip home.If Elizabeth randomly chooses her ride in the morning and in the evening, what is the probability that she'll use a cab exactly one time?
Options Combinations: Elizabeth has 3 options in the morning and 3 options in the evening, making a total of 3×3=9 possible combinations for her round trip.
Morning and Evening Cabs: To use a cab exactly once, Elizabeth can either take a cab in the morning and not in the evening, or not take a cab in the morning and take it in the evening.
Probability Calculation: The probability of taking a cab in the morning and not in the evening is 31 (for the cab in the morning) * 32 (for not taking the cab in the evening).
Total Probability Calculation: The probability of not taking a cab in the morning and taking it in the evening is also 32 (for not taking the cab in the morning) * 31 (for the cab in the evening).
Total Probability Calculation: The probability of not taking a cab in the morning and taking it in the evening is also 32 (for not taking the cab in the morning) * 31 (for the cab in the evening).Adding these two probabilities together gives us the total probability of using a cab exactly once: (31∗32)+(32∗31).
Total Probability Calculation: The probability of not taking a cab in the morning and taking it in the evening is also 32 (for not taking the cab in the morning) * 31 (for the cab in the evening).Adding these two probabilities together gives us the total probability of using a cab exactly once: (31∗32)+(32∗31).Calculating this, we get (92)+(92)=94.
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