Question

Justin lives in Saint Paul and goes to school in Minneapolis. In the morning, he has 3 transportation options (bus, cab, or train) to school, and in the evening he has the same 3 choices for his trip home. If Justin randomly chooses his ride in the morning and in the evening, what is the probability that he'll use both the bus and the train?

Answer 1

The train because it’s faster and he will get there on time

Answer 2

Answer:

The probability is 0.2222

Step-by-step explanation:

There are just two ways in which Justin use both the bus and the train on the same day:

1. He used bus in the morning and train in the evening

2. He used train in the morning and bus in the evening

Additionally, every day he has 9 possible ways to used the transportation, 3 in the morning multiply by 3 in the evening. This is:

        3         *         3           =  9

   Morning         Evening

So, the probability is calculate as a division between the possible ways in which he use both transportations and the total possible ways. This is:

$P = \frac{2}{9}=0.2222$